|
Engine Mount, Gear Legs |
General Hi all, Just for an update... I had Don George run my engine on a test stand and all went well. It's already mounted on the airplane. With the battery and wings installed, no weight was needed on the tail to hold it down. Also, I changed the oil filter yesterday and it came off with ease clearing the firewall by at least 1/8" inch. Finally got this alternator thing figured out with the help of Bil Asbell. The vans steel bracket kit works with the suzuki alternator. Am using a 36" belt (large flywheel pulley/stock alternator pulley) and all is well. I have the alternator pinout if anyone needs it. The engine fit right up to the lord mounts and the bolts needed two washers added to make their length correct. Regards, Bob Gross I'm at the stage of working through engine options and have found a wide variety of prices, including the following two examples, both for an IO-540 C4B5: 1) A certain well-known engine overhaul shop, which will complete the overhaul for $15K on a core I supply. Figuring a core is around $6K-$7K, this means about $22K all-in. 2) A shop which is not a "Lycoming Certified Repair Facility", which will sell me an overhauled engine with logbooks and all accessories for $15.5. Can you guys provide any advice as to what I should be looking for, to be sure I am comparing apples-to-apples? Thanks, Dave G'day Dave, The overhaul requirements we work to down here are the same as yours, so we have the same price variances as you for seemingly the same job. The biggest single dollar item for an engine overhaul is the cylinders, and a cylinder can be legally zero-timed for minimum cost by some magna fluxing and fitting a set of new exhaust valves & retainers. A more expensive & reliable overhaul will include pistons, valve seats & guides, which takes the cost from Aud$250 to Aud$1500 per cylinder (Us$1=Aud$2 roughly), and a new cylinder kit from Lycoming is about Aud$3000/cylinder. The same applies to the (expensive) gears in the accessory case - changing them all is not a requirement, but is a good insurance policy. Whoever you use for your engine, try and find out how his customers feel about him before committing a large pile of dollars. Cheers, Ron Graham (Oz) I think Bob Gross can shed some light on this: some shops will keep all the tolerances on the close side, where others will use the wide side. Big difference in longevity here! So, ask those shops for exact specs (bearing clearances etc) before committing. Cheers Mark Wow, what a big question... I overhauled mine myself. I saved big bucks ($10,000), but I'm not sure I would do it again. Sure I learned a lot, but I also learned that the guys that do engines full time REALLY know their stuff. All seem to have different opinions about bearing clearances, all seem to agree that lycoming cylinders are the worst, and most agree that cams and cam followers can be reground. Any shop that tells you "It will meet MANUFACTURER standards, this is the cost" should be avoided. You get to decide what parts you get, what clearances, not the builder. At the price of new cylinders, I wouldn't even consider OH'd cylinders even if the were free. They're gonna crack again and leave you stranded. I choose 6 new ECI cylinders as they were thought to be the best by most engine builders I spoke with. They also only cost $860/ea. As for the crank/rod bearings, here the builder can make big bucks off the unsuspecting buyer by returning what I consider to be a worn out crank back to service. He saves $1000 in grinding costs and oversize (expensive) bearings and you get an engine that clanks and knocks just like it did before teardown. (it will still last to TBO though..hey everyone...here come Joes' F1.....clank clank clank...) Had I to do it again, I would buy my core, disassemble it, send the parts out for recert/inspection myself (DIVCO, Elliot Crankshaft in Orlando, D&S Camshaft etc), gather all the parts I need and then take the whole lot to my favorite engine shop (Don George engines) and have his boys assemble and test it (while I watch and learn for two days). It's a GREAT education, saves big money, and gives confidence in the engine as well as ones ability to repair it in the future. Heck I built a whole airplane...doing the engine should be fun as well. If I weren't cursed with this darn DIY disease, I would probably hire Bart Leblond to build the whole engine as his reputation remains impeccable. BTW, Bendix mags fit fine on an F1! Warmest regards, Bob Gross Air FilterMark K&N p/n 33-2104. Mark Alternator Still struggling with this alternator thing. Here is what I have found for your own reference. First of all, I needed to put up $35 for a core charge on all the alternators but vans. I ordered the 35 amp unit from vans for $165. The parts arrived and had already been installed and were covered with corrosion so I sent them back. These 1978 Honda civic alternators have quite a bad reputation for not lasting more than a couple of hundred hours. They are cheap $21 at the auto store, but seems like too much trouble changing alternators every year. BTW, they need and external regulator $40. I spoke with the alternator guy at vans about this stuff. He told me to do as he had, and get a 60 amp unit from a 1989 Camry. I bought one for $99 and it came with a lifetime guarantee. It was a the same size as the Honda, but heavier and built better. It had an internal regulator set to 14.8 V, and the test sheet showed it belted out 83 amps! Still not being happy, I did some more research and came up with a 1989 Suzuki Samurai alternator (Nippon Denso) for $109. Now this thing is a little jewel (see pic). It is tiny, light weight and belts out an impressive 55 amps. Internally regulated to 14.6 V. Only problem is it won't fit the Vans bracket (see pic 2). I will be using this style alternator. Any of you guys know of the different part number that has a different mounting ears cast into the alternator? I saw a picture of one with a single large lug rather than the two small lugs you see in the picture. Both of the latter units are designed for high speed ops and do not need to have a pulley change according to the guy at vans. If you have any secrets on alternators please post them here for the F1 tips list. I have one like described here on my ship. Fits up ALMOST perfectly, and seems to last a long time. YMMV. Mark This from Bill Asbell: > Auto-Zone haz `em--Dura-last#14824 $102.99 plus $55 deposit so up hyar it > came t` $165.99 tax and all.Tell them to punch in#871772 14824 on the > computer and it`ll just jump out at `em.How did you mount the silly > thing??? NO!NO! not your first ----in High school the alt.!!!!!! As he > was heard to say DOH!!!!!!!!! Thanks BA > This from builder Bill Asbell.... Hey Bill: Is this one of 'em with that lifetime warranty too? Seems a breakdown enroute would be an easy repair -- availability almost anywhere! Did you happen to get the wiring plug to fit the thing too? I always had to go to the boneyard to get one -- even the dealership doesn't carry 'em. Also: while you're there, get one of those one-size-fits-all nifty chrome alternator adjustor arms (Mr Gasket etc) if your engine didn't come with one. Trim to fit your application! Be sure to use a drilled-head bolt to attach the arm to the engine. Drive belt: this varies with flywheel drive plley size, but I have a 30.5" belt on my ship. Be sure to get the skinny lil' fella that fits the alt v pulley. Keep the alt as high as possible for cowl clearance -- it should almost touch the right front baffle. If you have a drive belt installed, let us know what size you found to fit please. Hey guys I`ve spent the last 3 days trying to get the "SPRINT" alt to line > up on the available mounting.The thing is off by 1/8 of an inch at > best.I`ve used the 2 mounting brackets form Lyc,washers and a considerable > amount of colorful language.Mark--I`ll be calling you some time today and > see what if anything can be done diff.It`s rapidly approaching tain`t worth > this amount of time and effort.I`m thinkink a BC alt-bolt it on and get on > with something else Hey Bill: Geez -- I can't help you there. I have the Lyc mount tabs, and I installed a new alt last year with at least 3 minutes of grueling work. I don't remember any mods, tho I do recall grinding a bit on the attach boss of the previous alt to get the pulleys to align. Cheers Mark Mark--the one piece bracket will work great with 1/8in ground off and that will put it in alignment V-V.Thanks about the tip grind or malletize it to fit----RIGHT????Could you please give me some details/spec`s on your inverted system.If``n I think I can get it to work on my Super Stinker(in progress)I`ll try one. Bill#32 All this alt. talk has me turned on. I used the 55 amp Mit. It mounted up Mark, the normal range for Mr Voltmeter is 13.8 - 14.2v, & internal I have misplaced, O hell, I lost the name and # of the engine baffle builder. Could one of you more organized ( or possibly it has to do with my lack of brain cells) builders remind me. Craig Lefever email; feeve80@aol.com 520-603-0768 In Tucson AZ I'm also on the F1 web site under helping hands. Craig I am fitting up a set of Craigs excellent baffles to my engine. Those of you who have mounted your oil coolers, would you mind sharing photos/techniques with me/us. BTW, everything I heard about the Vetterman exhaust was true. I fits perfectly taking about one hour to install! Thanks Bob Gross Need some help on the baffling. My question is... What occurs at the intersection of the engine air inlet lower glass surface and the AL baffle (horizontal shelf-like piece) on the front cylinders? I seem to me that they must butt fit very close to prevent airleaks, but maybe there is some type of sealing going on there? If so how? How much of a airleak gap is ok at other locations? None...1/8"... 1/4" etc.? Anyone know how much the engine moves during operation? How much clearance is needed between baffle AL and the cowl along the side baffles? Regards, Bob Gross I have finished my baffles. There is at least 50 hours of work in them including Dave I installed a fiberglass plenum from sam james aircraft on my rv-6 some years ago this modification included using the round 4" ID airfoil aluminum inlet rings (supplied by Dave Anders) that reduced the cooling air inlets by about 40% Sam james indicated that this would be a 7 mph increase,however I could only see 3 mph increase I also installed the 3" carb. airfoil ring I saw a 1to 1 1/2 increase in manifold pressure these modification are a lot of work that took me all winter to complete, cooling in cruise was very good ,however in climb it would heat up faster oil was also running abit hotter the set up that mark runs should cool abit better do to more differential pressure with no speed increase because the of the same inlet size (cooling drag is the same) I would not do it again however, marks set up with the metal plenum isnt much modification for a bit better cooling. Best Regards Scott Seabourn Hey Dave: Cooling is definitely better. Weight should be about the same. It is a bit more difficult to get at the top of the engine, but that doesn't happen often. I suspect drag is the saem, as we didn't mod the inlets. We want to try smaller inlets, along with an extractor/augmentor arrangement. We'll likely try that this winter, after we get the Evo wings installed and that flgiht testing done. Cheers Mark Rocket dudes I can assure you the air cannot and does not know the difference between a pressure plenum made from the top of the cowling and sealed with flexible baffles or a solid plenum made from AL or Glass. The two most important factors for good cooling and low drag are properly shaped inlets and no, as in absolutely NO leaks. I believe the performance difference people see when they switch to a engine mounted pressure plenum results from improvements in the inlet geometry and by sealing up all the leaks. If one is careful, and with allot less work and less weight, the inlet geometry and the flexible baffles can be just as good as the new magic solid plenum. (BTW Technically they are both plenums but I know what you mean when you say plenum). I have noticed many ships allow air to leak around the spinner area thinking the air will not turn around and go forward, it will. Also another area of large leaks I see is at the lip of the fiberglass inlet and the ramp of the metal baffling in front of the cylinders, this is a difficult area and required some creativity to make it water tight. I ended up attaching the flexible baffling to the cowling and overlapped the metal ramp on the top, rather than trying to get a seal in the other direction. The rest of the baffling is straight forward, and all leaks are sealed with silicon. I created large ramps in the upper cowl and smoothed the airflow as much a possible. This is hard to say if its working or not, I suspect there is much turbulence no matter what you do once the air is past the first pair of cylinders, but it doesn't hurt. Also, oil coolers should be mounted such that a long flexible duct is not needed, as that will hurt oil cooling efficiency for sure. The decision is yours, I just wanted to point out that it can be done either way with equal results......And No leaks. Greg Nelson N144X My RV-6 doesn't have a plenum and if I didn't have ten million things on my things-to-do list I'd put a plenum on, the top cowl blows up like a baloon at cruise and I can watch it vibrate. Just from the standpoint of reducing engine contact area to the cowl will help keep your paint from cracking, rivets loosening up, hinges wearing, etc. Recently I helped my hangar mate get his prop dynamically balanced on his -6A and I really paid attention to how much the engine moves around during start/shutdown with the top cowl off. Even after balancing it oscillates about an inch at the front of the engine. So if you decide to not put on a plenum give yourself plenty of room for the silicone seals to do their job. Three-blade prop would also help in this regard. Regards, Bob #80 From an aero efficiency standpoint, louvers are not a good way to expel air from the cowling. IMO sizing the air out let properly is the key. 15% larger than the air inlet is a good start. If you find your outlet is too small, then adding louvers will probably help. When calculating the size of the out let, make sure you subtract things that block the flow, namely the exhaust pipes. This is what I did on my ship, I adjusted the bottom cowling such that I could calculate the area to be 15% larger than inlet area, and I have no louvers and cooling is great. Greg Nelson Louvers are not made to expell all the air from the cowling. They do have a Hey guys - what's the standard thickness for baffel material (the rigid part) - .032? We used .032 here, but make sure it's 6061-T6 to handle the vibration. Mark I used a soft alum .050 hoping that it will stand up a while. For the lower part that wraps under the cylinders I used a harder .025. I had a band saw to cut the shape around the valve covers. Once you get a good one you can use it as a pattern for the others. Jack #70 Bill, You're smart to build the baffels yourself; I've been fitting the kit for I'm sure 20 hrs and still it doesn't fit and I'm not finished. Tom Martin did it the right way. Bob The Positech 20006C and the Positech # 4219 are the same part.billy waters The one Mark sells Jack Jack Is it a # 20006C? Thanks Bob W Fellas: There is NOT a problem with the cooler, or the cowl configuration that we can see. I ran WFO for 20 min during the Sun 100, and saw normal temps the whole time (185F oil; 325F CHT). We are looking at reducing the inlets a bit.. Quite different from my other ship, but it has a cooler the size of a paperback book. OK for cruise, but not for much higher power settings. Low drag, for sure.... I suspect a step in the cooler inlet ramp is causing some turbulence in the duct. As fo using SCAT hose for the duct, this will take some experimentation to get right. Have a look at the FWF pics in V2.25 to see how we handle it. As for climb temps, they do come up a bit, but Lycoming says anything below 245F is fine. My personal limit is 230 in climb, and 210 in cruise. YMMV... Interesting results with the water dampers. I might try that too, along with some different weights of oil (ATF, engine oil etc). Seems that a horizontal 1/2L water bottle set into the aft area of the pant would be easy enough to do, but that effectively lengthens the tuning fork length.....will this be a problem? The fwd location also 'balances' the pant, more or less. The wood does a fine job, but easier is better, esp in the case of a retrofit, as some will be. Cheers Mark The positech cooler # is PC# 4219, billy waters Bob - I've been fishing the last two days (only one bass, too late in the season, but a lot of crappie). I looked up the reciept andit says Positech #4219 Jack Jack I have a Positech # 20006C which I think is their latest and best. Give them a call as they are very accommodating. I have also been told that Niagara makes the best cooler so call them also. Sorry, I don't have the numbers. If you call Niagara let me know how you make out. Blue skies Bob W The Positech 20006C and the Positech # 4219 are the same part.billy waters
Hey guys, maybe you can help me.. I finally am up and flying #001 after 11 mos of First, keep the speed up, I have found that things cool best at 140 KIAS and Larry, This is a bit like using Luis' hammer to drive a tack, but the single engine Bob..Im using the old style cooler from Mark.. I did call the positech people yesterday Engine CLearance I'm trying to hang my engine, and note that there is very little (1/8") or so clearance between the fuel pump and the firewall, and the oil filter is just touching one of the top EM tubes. Perhaps a shorter filter will help? What filter are you using that fits? Thanks, Scott Roth What filter adapter are you using? B&C 90degree, CH48108, misses by about 1/2 inch, but thats enouph. Greg Nelson N144X The fuel pump is ok. Mine is that tight and never hits. The oil filter seems a problem. I use the stock lycoming filter adapter and it clears everything fine using a CH 48110. Warmest Regards, Bob Gross
Engine Preservation Hey Bob - Kool shades!! How long was your engine assembled before you started running it? I'm expecting to have mine on the mount for 6-8 months before flight testing. Any recommendations on best way to prevent rusting while in the construction phase? dessicants, plugs, etc??? Regards, Bill On my eng. I flushed the entire eng with Nitrogen ( Dry Stuff) . This is Great Idea. Hope it doesn't leak out. My buddy filled his engine with inexpensive oil to preserve it, 36 quarts. I like that idea also. Warmest regards, Bob Gross Guys, Being a lab geek for 20 years means that I know a little about drying things... like engines. Sure you can fill the crankcase with oil if you want to. Kinda messy when it runs out of all the holes you forgot to plug though. And it doesn't necessarily remove the moisture!!!!! Here's what I suggest... YMMV. Put fresh oil in the engine or just drain all of it out. Take out all of the spark plugs, actually all of the engine openings should be open for best results. Get a couple giant garbage bags or make the equivalent from plastic sheeting and duct tape. Put the engine in carefully so as not to tear the bag. Toss in several bags of drierite (see the website). Seal the bag. Monitor the indicator every few weeks and rejunvenate the drierite as needed by baking it in a oven as shown below. The drierite will turn from blue to pink as it absorbs water. Water can only come from the engine or a leak in the bag. You should reach a point where the drierite stays blue indefinietly. When it does your engine is bone dry. http://www.drierite.com/catalog3/page16.cfm If you do this right, I GUARANTEE that your engine will stay absolutely dry. Period! And it's really quite easy to do. Vince Frazier I have used my modern microwave to bake the stuff too...the oven does fill with moisture! Mark Yes, that works too. But under certain conditions (such as little or no moisture to absorb the energy), your microwave will turn inorganic materials (like drierite) into white hot balls of plasma. Quite spectacular. I've seen it in the lab and I don't think it will give Mama a warm fuzzy feeling if she sees it in her kitchen. Better stay with the oven. FWIW, my engine is just sitting in my shop (heated and central air), no oil or drierite. But if you have to do an extended storage in a damp area, either oil or drierite would be good. YMMV. Vince Engine Mount Bolt Torque Does anyone know the torque required on the engine mount bolts (from engine to engine mount). Have seen two different ways illustrated on which way the isolators are to be put on, I think the hard ones should go aft on the bottom and the hard one should go forward on the top to hold the weight when sitting on the ground. What do you guys think? John Wach #96 John Send me your Fax # and I'll send you the Barry Controls install sheet. The ones with lines go on the rear at the bottom and towards the front at the top. Bob W Hey John: Torque specs are per AC43.13 -- it's a bunch on those 7/16" bolts! The two diagrams are for the 4 cyl Lycs and the 6 cyl Lycs - be sure to get it right! I can FAX you a copy if necessary -- send me a FAX number and I'll do it tomorrow. Cheers Mark
Exhaust Coatings Has anyone considered using ceramic coating on their exhaust to help keep the under-hood temps a little cooler? I understand that some builders find blistered paint/etc on the cowl after a few flights. I've seen it used on hot rods quite successfully. Scott Roth used it, looks good, don't know if it helped the under hood temp. but I have not had any problems there. The only problem with it is if you get a crack you may not be able to repair it. The cost of the coating is almost as much as the cost of the exhaust system. Jack #70 As a precautionary measure, I plan to install some thin aluminum protective sheeting on the inside of my cowling, closest to the exhaust pipes. Over time, the exhaust on my RV-6 caused a couple of paint bubbles. This happened after about 150 hours. Van's sells this stuff and it's cheap insurance for an expensive paint job. You can see where I've used this stuff on my Rocket to protect the inside of my wing tips from the heat of the landing light. Go to the "Wings" section under "F1 Rocket Project". Randy #95 (also trying to contribute) Hey Scott: If you do this (I've seen it on quite a few ships), be sure to tell 'em to NOT coat the area where the heat muff will go. This stuff is so good that you'll get no heat! I haven't heard of any paint blistering problems with the F1, except the leading edge paint...from the high speeds... nyuk-nyuk... Mark How close do the pipes get to your cowl? I have the Skydynamics 6 :1 system and seem to have at least 2" everywhere. I will be ceramic coating as well with the Jet Hot system. scot Scott I also have the Sky Dynamics. I understand that Kevin does not want coating done to them. How did you handle the lower cowl clearence? I am thinking of putting a rounded section to go around the pipe so that the rear edge of the cowl will be straight across. Blue skies Bob W Do you have to add protection to the belly of the aircraft some way if you go with a collector-type exhaust system? Thanks, Mark Swaney I am coating anyway. I am going to make a aluminum insert with louvers as seen on Blackjack but will do as you have stated by adding a rounded section into the aluminum plate the goes around the exhaust collector and maintains a straight aft cowl line. scot I saw this on one HR2, and I told the fella to have his shop put a turn-down on the thing. This particular HR had aT28 style exhaust streak all the way to the tailwheel -- very messy!! So, ask Kevin to put a slight turn-down on the end of the collector, please. Cheers Mark On my RV-6, the pipes were less than 1/2" from the cowl where the pipes came together and ducked under the mount and out the bottom. If you have 2", I think you have more than enough airspace to render the "protection" issue moot. I don't see where coating the exhaust will buy you much either, but I'm not much of an expert on the issue. My concern is that the coating will mask your ability to detect cracks until something potentially falls off. I don't think that heat is much of on issue on the output side of the cowl provided there is enough exit space provided. Randy #95 I just talked to Kevin. He dosen't like coating but said that if you do it make sure you do the inside also otherwise the heat stays in the pipe and the stainless temperature gets too high. He said welding is almost impossible after coating and the coating changes the metalurgy causing cracks that can't be repaired (FWIW). He said that the outlet had been turned down to some extent from the original but it is going to be LOUD. I plan on good insulation on the belly interior. Bob W Had heat coat on mine for 200 hrs. and like it. Also tell them not to coat the slip joints had to grind the hard stuff off. Craig There was some problem with scorching on Rob Mokry's plane so Skydynamics turned the tip down just a bit. I think it solved the problem. I saw another idea at Massey aircraft. They add a stainless plate to the belly from the firewall back about 12". I think they sandwiched a piece of high-temp insolation between the SS and the aluminum belly for extra measure. scot More worried about the excess radiated heat in the engine compartment. The coating helps to keep it in the pipes and out the exhaust tip. The masking of cracks is a new one I hadn't heard about this stuff. I will ask more questions of the Jet Hot guys. scot What do you do about the heat muff? Bob W If you mask off the areas that you don't want the coating the Jet Hot guys will make sure it does not get coated. scot Hey Bob: I'd look for 1" clearance in this area if the new pc is composite, maybe 1/2" if aluminum. You might want to coat the area with fiberfax for heat protection, like Bob Gross used -- I think he has some extra leftover pcs. I'll bet that collector gets hot. Looks like you gonna need some firesleeve around the engine control cables too...the inside plastic sleeve can be melted with relative ease. I'll bet it sounds really good. Too bad it's gonna be slower than mine. I guess you can't have it all.... Pretty funny, for a Monday, right? Heh-heh... Mark They do coat the inside and that is a good question on how they avoid the masked area. More good questions for those guys... scot Hey Scott.......... You might want to check out the guys at HPC www.hpcoatings.com. They've done the exhaust coatings (and redone jet hots job) on a couple of OshKosh winner's planes for us in KC. They seem to be very customer friendly and provide a good long lasting coating. We had problems with discoloration on one plane and internal coverage on another when the parts were coated at the Jet Hot facility.......... Chuck Nuffer s/n 82
Exhaust System (Vetterman) Mark - the hangers supplied with my Vetterman exhaust system consist of rubber doughnuts and eye bolts. Much different than the ones shown in the assembly manual. Any preference?? Bill, I think the type you have will let the exhaust ride up and hit the fuselage while is fast flight. You need to have a fairly rigid rubber bracket attatch. If I can figure how to send pics I will send a pic of mine...billy waters Bill, The donuts are the latest greatest system. I've had new and old, you don't want the old hangers which were rubber tubes. I needed to add a rubber tubing connector between the two pipes to finally get them to stop banging the cross tube. Larry says only a few exhaust systems give any trouble. I had to pop rivet my slip balls to keep things in line until the balls froze up (normal) from carbon. Now all is well. Warmest Regards, Bob Gross Bob - thanks!! - what's a slip ball?? Bill It;s the ball joint located about one foot from the pipe outlet. The tail pipes can swivel around (for a while) as these joints are shaped like a ball. Warmest Regards, Bob Gross Bill I have used both systems, the newer hangar style on the F1 and the older style on my Harmon. I needed to add a cross piece between the new system to get it to work for me. It is a bit simpler than the old system and will work fine. The old system needs a couple of minor mods to make it work. The first one was to throw away the white adel clamps that came with it. They would not grip the motor mount tight enough and would rotate with use. I also removed the cross piece in the middle that was fabricated with tubes ann a rubber piece and replaced it with just a flat aluminum bar. The key to the older hangers is that when you get them in the place you want them, sqeeze the end of the metal tube with the rubber tube in place, just a little. This will put a slight flare in the metal tube that will keep the metal tubes from sliding in the rubber ones. Tom Martin
The eyebolts and the rubber doo-hickeys work very well indeed. we get everything arranged as required, and then drill for 2 ea 1/8" steel pop rivets thur the ball joints to hold the rotational angle right. By golly, I'll get some pics inna manual ASAP! Cheers Mark The reason Larry has been trying different hangers is because they all fail. The claims of only failing on a few airplanes is a bunch of bullshit. I think I've replaced hangers on the RV four or five times now. As Tom mentioned, I made the cross piece out of 1/4" aluminum bar after I kept breaking the hangers. Since I went with the aluminum bar I have had no problems, and that was probably 150 hours ago. Having the aluminum bar holding the pipes across makes them a little bit more rigid but it will still move, and cured my problem with backfiring on short final causing the pipes to bounce up and hit the belly skin. Its interesting to note that John Harmon's exhausts don't have the ball joints in them, and there are no hangers to support the latter part of the exhaust pipes. Regards, Bob
General question...what electric fuel boost pump is the unit of choice out there for the IO540? I use a high pressure Dukes fuel pump mounted just aft of the firewall. This is a direct flow unit, by that I mean that no bypass plumbing is required. During use it puts out 26 psi, and when off the engine driven pumps shows 23 psi. I use the boost pump for starts, take offs landings and when changing fuel tanks. I have close to 1000 hours using this type of pump on three airplanes, with no problems at all. Tom Martin I hear some are using the Dukes pumps, but I have Airflow Performance pumps on my ships. These have a bypass feature (in the event of certain modes of boost pump failure), and cost only $375. I suspect the certified Dukes is $500+? If you buy the whole AFP system ($2560 for ALL the parts required to install an FI system on the F1, down to the elbow w/ adapter & drain valve, injector line clamps, & screws!), the pump is included for substantially less. A new AFP throttle body runs $1250 -- and give more torque too. Keep this price in mind when considering an O/H for your Bendix. If the upper parts (lines & flow divider) are OK, these will work with the AFP throttle body. Throttle Body elbows: Of course, you all know you will need one of these, to get the throttle body laid fwd as required bt the intake design. Plan on adding $219 to the price of the AFP throttle body (these parts are included in the kit), and plan on $122 for the elbow to fit the Bendix. And then there is the Christem wobble pump, which can serve as a boost pump. ACS carries these. I hope this helps! Rocketiers Fellas: I bought the Aeroquip hardware and hose from Summit for al my planes over the Fuel Filters. Hey Gang, check out these K&N Fuel filters. Way less expensive than the AFP filters. Big ones with #6 fittings are $76.00, small ones are $58.00. Eric http://www.knfilters.com/fuelfilter.htm Eric: > Just wondering if the flow rate will be enough. I know my > engine at full > power demands 26 GPH. Maybe the guys flying can comment on > this for us. > Saludos, > Luis > #21 Just make sure you avoid paper elements, they absorb water and may stop fuel > flow altogether. > Another urban legend! Do a search on the RV list under paper element filters. You'll find where a gent soaked the paper filter in water, then put it in the freezer, and then tried to run gas thru it. No problems! Why do I care? I have paper element filters in my ship; one has 760 hrs on it, the other one gets changed at annual. I figure that if these things were the least bit troublesome, modern autos wouldn't use them: owners would NOT accept such a liability. Heck, I have 150K miles on my Chevy pickup, and it's never had the filters changed either. I always figured that if one filter plugged up, I'd simply switch tanks. Well, one fella pointed out that such a problem would likely be from bad fuel just purchased. It's also likely that both tanks would have the same problem, and turn my airplane into a gravity powered ship anyway. DOH!! Unless the filters would let the water pass thru...enough to let the fuel system start working again.... Your call on the filters -- my experience has been OK with 'em. Cheers Mark I am using fuel filters ordered from Jegs hi performance Auto (800-345-4545) and really like them. They are high quality Aluminum with stainless steel interior, reusable and come with AN-6 fittings. They handle my max fuel flow (about 28 GPH on takeoff) with no problem and measure 2''X4''. P/N is 888-201406. Name is System-One Prostreet. Cost is about $90 each, but you will use them the life of the aircraft. GlacierGeneral Wisdom Please Should I place the inline fuel filter prior to or after the electric boost pump. I have initially ordered the System 1 units that Jim Cash discovered, they flow 540 GPH, 9 GPM and the reusable filter goes to 30 microns. I noticed van's sells the airflow performance unit for 130, I am checking it out today. At Ellison injector website the excellent article there cautions on leaks upstream of an electric pump induced by sucking. The only logical alternative is a single filter unit downstream. BTW thanks to all for the insights on pressure transducer locations......another error averted! Thanks Howard #3 ghrhodes@midsouth.rr.com I have an airflow inline on mine and it works fine. Easy to maintain. Mine is after the T and before the pumps. Craig Lefever Fellas:
General Wisdom Please Should I place the inline fuel filter prior to or after the electric boost pump. I have initially ordered GlacierMy fuel filters are located between the wing and fuselage before the fuel pump---work great, and outside the cockpit--- Mark, what is the AD on the SS injector lines, This is the first I've heard of it. I can guess that it was a broken line due to The lines should be supported every 6 inches. There is a Lycoming SB on the matter. Regards, Bob Gross Correct: it's the SS 'spider' lines, and those must be supported every 6" or so, no nicks or kinks, etc -- check the AD for exact data. My fuel filters are located between the wing and fuselage before the fuel > pump---work great, and outside the cockpit--- Greg, this AD is an important one. A Rocket owner by the name of Dalman did support the individual fuel lines to each cylinder every 6" on one side, but did not on the other. Guess what! A line on the unsupported side broke, caused a fire and Dalman tried to make it home---about 20 miles away. He had a patched hole in the firewall supported with aluminum rivets. The aluminum melted giving rise to a blowtorch coming into the cockpit. He landed the airplane and died about a week later. The back seater suffered no ill affects. If your engine was built up by a good engine shop this AD has been complied with. If not, you need to call your local FISDO and get a copy of the AD. Jim Cash Try and mount your fuel filters outside the cockpit---makes a leak a bit easier to live with until you get on the ground. I mounted one on each side as the plumbing exits the wing---works great. I used an Airflow Performance fuel pump from Bart LaLonde for around $300. I did not know about the auto pump available thru Jeg's Auto for $90 that many HRII guys use---works great. Email me off line for the numbers if interested. (jcash@centurytel.net) Again, I suggest everyone look at the fuel fitting available thru Van's that gives you a "T" right out of the fuel pump for fuel ine to the servo and to the fuel pressure transducer. The Part number is KB-090-T. Take your fuel pressure from this point-not the fuel divider. GlacierI mentioned I was going to check out the Airfow Performance filter.....here are the numbers. 720 GPH 125 Micron steel mesh filter .5 PSI pressure drop 132 dollars from Van's or Airflow The folks at Airflow assure me one of their filters upstream of the pump is the ticket, also that low pressure drop is the key piece of data to avoid vapor formation, turbulence etc.. SOOOOO, I am placing one of theirs upstream of the pump and one System one 30 micron DOWNSTREAM of the pump. Louis at System 1 is testing a unit for pressure drop on the flow bench.....it is not on the tech sheet. May be overkill here, thoughts?, pitfalls?, better ideas? Kinda an important system. Nice Weekend Howard SOOOOO, I am placing one of theirs upstream of the pump and one System one > 30 micron DOWNSTREAM of the pump. Louis at System 1 is testing a unit for > pressure drop on the flow bench.....it is not on the tech sheet. > > May be overkill here, thoughts?, pitfalls?, better ideas? Kinda an > important system. > > Nice Weekend > Howard Hey Howard: After seeing some of the crap that comes out of fuel tanks (alum shavings, sealant pcs)...for a LONG time after completion, I'd say the first filter is necessary to insure pump survival. Due to the difference in micron sizing, the second filter sounds like $132 of gas money spent elsewhere. My 2 cents... Mark Something you might consider. Mark told me to use fuel filters located in the Hey Ron: Your engine is auto-leaning itself a bit (not full MP there), so Russ- > > My field elevation is 4,230 so I don't get to sea level much. Ron, > > What's your takeoff fuel flow at sea level? That is a pretty Hey Mark and All, a properly leaned engine, consuming the correct Hey Fellas: I asked the MT folks, and the Hartzell folks for that matter, I have been flying around in boxes gathering performance data for the last few Hey Fellas: Am I in trouble? I came from the fuel pump with a stright 3" alum tube to a Mark not only that, but you will read about 6 PSI up there after the fuel goes thru the servo and divider. Mark What`s wrong with tapping fuel press off the flow divider on top of the engine? Well, that pressure changes with throttle setting & mixture etc. The flow gages that read from there translate There is only one manufacturer of fuel-flow transducers used in aircraft, and that is FlowScan. Builders I mounted my engine today, twice. The first time everything went well until I I took a brass elbow and ground it down so that I could cut the threads all the way to the bend. I also ground Usually the soft metal lasts and wears out the hard. I think the soft picks up abrasive particles and grinds on A friend in an RV6 had his stainless exhaust pipe slip a little in the clamp and it contacted the lower engine One additional comment about Aluminum and Stainless, the two don't like each other in terms of corrosion. Say, speaking of fuel pumps, I'm about to order an engine, and it seems that there was some discussion about The overflow should be modified so it is positioned above the outlet. This requires some dis-assembly and Gents, Does anyone know if Van's RV4 engine fuel pump overflow fitting will miss the firewall on an F1? Ron I have not used the RV4 fitting but there is very little room there, my guess is that it would not. I have used that fitting, and it hits the firewall. Modify the pump, or put a little bump in the firewall. I did the could not put a bump in the firewall as the alum angel was directly behind the fitting. Also there was a revit Hey Fellas: Mark, where do I get these specialized in and out fittings for the stock > IO-540 pump? Apparently they include Hey Fellas: Hey Guys, what should the fuel pressure be? I'm taking it off the output of the mech. pump. With the engine Jack I get readings of 22 to 24psi, the lower with just the mechanical pump and the higher with the electric Yep -- too high. Should be around 25, but not much more -- maybe 26. I have my low press alarm set at 18 Tom - thanks for the phone conversation. I bled the fuel pressure line after I filled the sender up, no help, so I have a question for all you smart Rocket pilots/mechanics out there. Greg It sounds like you have a problem with the internal venting of your mechanical pump. Tom; Thanks for the fast reply. Can you elaborate a bit on the internal venting?, I did Greg This is an internal vent that allows air to pass back and forth between the upper In response to the fuel pressure problem, I don't know what causes it. My RV-4/180 on a hot day will drop to minimum on an A question to some of you guys already flying. How much unuseable fuel do you Two answers on the fuel: When I fueled my airplane the first time, I was only able to get 50 gallons packed Sounds like we're gonna be talkin' relief tube soon... Seriously, though, are those Van's tip tanks, or did you There are vents in the tip tanks and the instructions warn you to make sure your main tank caps seal properly. Jack, I have a friend that installed those tanks on his 540 powered RV-8. There's a problem in that if you gravity Here are a couple of pics of my governor installation. Note that I used a > 60" cable which is a bit on the short Hey Fellas: I supply a 66" cable for the gov., not 60". I am wondering why these governors are set up the way they are with the arm pointing down. Correct me if this It sure can, but then you would need a reversing quadrant lever(s). I chose to not go this route, to keep the You're kidding me, right? They would have to make the interior threading backwards, so the shaft comes out Gawd...I''m just asking, but I am serious! I like the idea of a straight run that way you have no binding on the Bob IFyou could change the arm to the top, it would be straighter, but the current set up works very well. I'm installing an electronic ignition and it tells you to put the CHT probe on the hottest calendar. Having not yet run the engine let alone flown the airplane this is a little tough. Can anyone give me a hint as to the best one to start with? Jack #70 N61R Jack If you have been following the rocket list thread, you will note that Tom Utterbach had #2 as his hottest cylinder. On my rocket #5 is the hottest. The point is that each installation is unique and all engines are not the same, this explains why many builders use a multi probe system. Having said all that, if I just had one probe, I would put in on the rear cylinder that is on the same side as the oil cooler. Tom Martin I asked and got so many different answers, I gave up and did like Tom Martin suggested. My single probe is on #6, same as the oil cooler. I'll be flying by Christmas (year unknown) and let you know how it worked out . ;) Regards, Bob Gross What do you guys know about tuning injector nozzles? I need to adjust mine > to getter more even distribution. Shouldn't this be dome the other way: note EGT at a certain fuel flow? Seems you could chart the cyls to see No way! Peak EGT temps vary for different cylinders. You want them all to peak at the same fuel flow. Bob W On second thought. Yes. If charting and it will give you the same result as it will show the fuel flow at peak for Absoultely! But, I refer to the tuning process, where you would lean to a certain flow value, and note the temps Absolutely absolutely. We are both saying the same thing but the chart is more fun and looks great when Bob and Mark are both right, of course. If you wish, you can get a more complete Jim Now that my #5 cylinder has a larger orifice, for cooling reasons, it peaks quite a bit after the other cylinders
I'll send a few pictures; gotta take em first. I originally mounted the cooler to the baffling, that did not work I'm making my engine wish list today and thought I'd throw this out there. Here's another cool product I did not know existed until recently. I am certainly going to run an oil filter on my engine, but man the cost of those remote aircraft jobs makes me whimper. For some reason I'm a little leery of the Summit racing remote units. So I think this is the least expensive option for aircraft from a company with a pretty good reputation. $225.00 is pretty reasonable for a product that they actually dare to advertise with the word "Lycoming" in the same sentence. Eric http://www.niagaraairparts.com/ Hey Guys, Do the 540's with the oil filter adapter use the Champion 48110? Thanks! Bob Yes my engine uses the 48110 filter. Tom IS that the B&C 90 degree oil filter adapter?? If so that is what I use on my ship, and I think I have maybe 1/2 inch clearance from the filter to the EM and I have no problems. Yes the engine moves around on the mounts, but it moves mostly in rotation about the crank shaft, and the oil filter is pretty close to on center line of the engine, so it probably does not really move that much compared to other parts of the engine. Side note: I also have the light speed ignition, two of them to be exact, but I mounted the High voltage coils to the firewall rather than on top the engine for two important reasons. Less heat, and less vibration, the two worst enemies of anything important. I had considered mounting them just like you did in the pictures, but finally decided that is probably not the best place for long term ignition health, and the wiring will take a beating long term. Those coils can be easily mounted to the engine mount and that will lesson both of the enemies. As always its ultimately your choice and YMMV. Cheers Greg Nelson Can you give us an update on the inverted system you plan to sell? When do expect it and how much? The machine shop is working on that still -- seems the dang slobber cans are gonna be expensive, unless we simplify the design a bit -- please stand by! I want the cost to be $450-500 for the valve, can, and vac pad adapter. You'll still need the fitting kit from Christen -- if we can get 'em to split up that kit, we can make some of the other fittings too. You'll be making the hoses yourself. Has anyone seen Raven Aircraft's inverted oil system, or used one? How does it compare to the Christian system for reliability, size, and weight? Also, has anyone had any engine experience (ie engine built by) with Ken Tunnel at Kendra Air Parts, or Ron at Performance Aero? Also, is anyone using cold air induction, and how does it fit under the hood? Just finished pouring my counterweights. They came out great, but it sure took a LOT of lead--And I thought I was trying to keep this as light as possible.... Regards, Scott Roth #93 I have one of these on the way here, now -- could be that I'll end up with an OEM from these folks. Please stand by! As far as I know, it appears to be a Christen clone. Could be that the valve is milled instead of cast... Mark Hi Fellas: I have received several emails recently asking my opinion of installing an inverted oil system on the F-1. Enough interest was shown to warrant a response on the list. Here is the downside, and it is for the guys still on the fence. Some have already made up their minds---please disregard, or you can contact me offline at jcash@centurytel.net. I have flown almost every modern US Airforce fighter in the inventory (almost all 9-G aircraft now), and none have dedicated inverted oil systems. Every air-to-air and air-to-ground maneuver is executed under positive "G". Negative "G" maneuvers were created by aerobatic pilots to look good from the ground---they serve no real purpose, however to compete they must be mastered. Point: If you plan to fly competition aerobatics you will definitely need an inverted system. If you plan to fly competition aerobatics in the F-1 be prepared for great disappointment. I remember an attempt by several folks a few years ago to compete with the RV-3. These aircraft will do sloppy aerobatics, but they will not compete even with a Pitts S1C. Now, what do you gain by adding the system and plumbing? Weight and cost. Note the cost of the hose kit alone runs around $600 over the kit (Van's catalog). And again, weight is everything in terms of performance in these little airplanes. I would ask myself just what kind of negative "G" maneuvers I plan to perform in the F-1 before saturating the firewall with such a system. Be especially careful if you are building the airplane to be certified IFR and plan to fly it that way. This is just one guys opinion---whatever lights your Rocket, as one of my old friends likes to say. Visit me in Montana and I will give you a memorable flight in an F-1 without pulling even one negative "G". Jim Hey Fellas: Jimmy makes several good points here. Hangin' in the straps is not really all that much fun (for me), but if you want to do that, by all means go for it! One thing to consider: if the prop gov loses supply oil, the prop will 'run away', and could actually fly off the front of the crankshaft if the engine RPM exceeds about 3500. Now, I have seen that it takes about 3-4 seconds of neg G to get the engine oil system to lose oil pressure (even tho I have an inverted system!) and the RPMs start to go up after that. The increase is rather slow (and controllable in the situations I have been in) with a Hartzell, but I would suggest it would be almost instantaneous with an MT. So, for the ship we are assembling here, I have picked a counterweighted MT (RPM willl drop if oil press is lost). I don't plan to install an inverted system, but the next guy sure can if desired. It's easy to do, even after the ship is built and flying. This type MT prop weighs about 55 lbs -- about 5 lbs more than a non-aerobatic version. I have no data on a similiar Hartzell, but I'd SWAG the weight at about 8 lbs more (80 lbs total). That's more than I can recommend. SO: if you decide to NOT install an inverted oil system, and elect to use a counterweighted MT instead, the $$$ will nearly match a std Hartzell w/inverted system would end up at, and the ship will be about 20 lbs lighter on the nose. Sorry to go on like this, but there certainly is more to the story than what appears with a quick glance. Cheers Mark Chairman, Group W Flying Club Hey Guys, I second Jim's opinion...more failure points, more places for oil to leak, etc. I know guys who have had inverted systems ending up taking them off because they generally proved themselves to be more of a pain in the ass than beneficial. I personally do brief negative-G stuff in my RV and I tend to get a headache later on...and I'm one who's flight isn't complete without at least one aileron roll. I enjoy positive-G aerobatics but dislike negative-G manuvers. My opinion is it's another thing to crowd your firewall for the rare times you spend doing sustained inverted flight. Bob #80 I agree with Gen Jim---the Rocket will get away from you real fast on some acro.The inverted sys is EXPENSIVE and adds weight you don1t need on the fire wall!!You can as Jim says do some mild positive "G" maneuvers,ie,rolls,loops and wing overs and have fun.IF you get the nose down as in falling out of a loop even watch the a/s indicator!!!! Speed in this case can kill cuz,Bubba if the ground looks close unexpectedly you will probably pull too hard and overstress the bird.Look at your maneuvering speeds-----you will get above that in a hurry and unless you are comp in basic acro,hang on it can get you into trouble in a heart beat!!I have a PITTS S-1S and fly acro LOTS and if for some reason I don`t fly for awhile(1 week) I notice that it ain`t what I`d like or as nice as it should be.45 minutes a week pract.acro is NOT unreasonable.I only offer this as I don`t want to hear about one of you "ROCKET" scientists bustin` yer ass!!!! Bill Asbell Confession: I have never filled engine oil on a taildragger. Should we What a great question. I fly a Cessna 195 and I am told that the dip Reed is correct here: you will need to calibrate the stick for the T/W attitude. I recall mine reads about 1.5 qt low: 6 on the stick = 7.5 in the sump. In addition, don't put 12 qt in the sump -- 10 max, else the engine will simply puke it overboard till it gets to 10... For local flying, I keep ole 84 at 8 qt; fill to 10 for XCY stuff. Burns about 1 qt/6-8 hrs. Mark Howard.. I only put 9 qts in my Rocket when changing and run it between 8 and Does anyone know the procedure for setting the oil pressure to higher limits on the IO 540 Eng. ? Mine is a little low at idle RPM. thanks billy 026. The oil pressure adjustment bolt is located on the right rear of the engine facing outboard should be about a 9/16 wrench give her a couple turns clockwise and see if thats enough. Scott Seabourn #18 About the only risk I can think of running the oil pressure up higher is blowing out the crank seal when the engine is cold. I imagine a plate can be fabricated over the seal to insure it won't pop loose. Regards, Bob I just ordered a new set of 6 ECI cylinders this morning and the shop which is supplying them mentioned that for an extra $200 per cylinder, they could port and polish, for a claimed additional 20 hp on the final installation. > > Anyone have any experiences or opinions on that? > > Dave Dave, IMHO on a Lyc. the valves don't open very far, and I would think this is the limiting factor on the flow of the fuel/air mixture. Since that can't be changed then there really isn't any point in flowing the cylinders. I don't buy their hp claims on porting and polishing. Lemme guess, you talked to Lycon? Call Bart, he seems to think this is bunk. Also consider the warm sump heating the mixture up, it may be wise to spend the money instead on a cold-air induction setup. Probably would get more bang for your buck, no pun intended. Just my $.02. Regards, Bob A bunch of shops that make this type of work usually claim a gain of 5 hp per cylinder. Reality, is about 2 to 3 hp per cylinder. Is it worth? I think it is. The engine runs much smoother. I had Performance Powerplants do my brand new cylinders. In the process, they found and rejected 1 valve, two seats and 1 guide back to the manufacturer. I repeat these are brand new cylinders, and they still rejected some parts. The limits of these rejected parts are acceptable to mass production of cylinders. However the limits are more strict when you get this type of work on the cylinders. My engine started at 260hp. I have standard compression pistons + airflow performance fuel sys + polish, hone, port, and balance. The engine came back with a test run of 285 hp. Not bad for standard compression!. Regards, Luis 21 Mark, > A while ago you mentioned that you were working with MT to see if you > could get a better price from them (competitive with Hartzell?), and if > they could modify the blade profile to better suit the F1. Any progress > in either of these areas? > Scott Roth > Yep -- that's all behind us now. The MT 3 blade appears to give similiar performance to the Hartzell 2 blade, and virtually identical to the Hartzell 3 blade. Pricing is close, now that we are into FY2003 for Hartzell: the Hartzell will run about $8500 w/composite spinner; the MT is about $8750, again w/spinner. Shipping: the Hartzell ships from Ohio, which is not too costly ($200 or so). The MT can ship un-assembled from Germany to an assy shop here in the US, adding about $550 (shipping + assy) to it's cost, if the assy shop is convenient to your place. If it has to be shipped from the assy shop, or shipped pre-assembled direct to you, add about $1000 to the price. Clear as mud? Cheers! Mark Mark, What is the weight of each of these three props? Dave Gents, There are some archival notes about the development of the MT for > the > HR/F-1... what is the current status if anyone is running the MT ?? Mark > ?? Hey John: MT has designed a blade special for the F1/HR series. It does work very well indeed, as I see the same IAS at the same RPM/MP/fuel flow as before. Smooth as a watch, too. This particular aspect is eerie -- you absolutely canot tell any RPM change if you are judging from the vibration frequency -- you have to watch the tach! The blades are tuned to 2100 RPM @ 10,000MSL, as is the 'D twist' 3 blade Hartzell. > > Quest: 1 How does the MT @ 52# compare with Hartzell 2-blade for weight? No change, if you use the non-coounterweighted version. > 2) Is it compatible with the usual governors ? You bet -- no change. Due to the very low blade inertia level, MT recommends using a faster acting gov, like the CZ units we sell. These govs are 2 1/2 lbs lighter than a comparable Woodward, and cost $1150 new. If you are not going to run an inverted system, I'd recommend using the counterweighted type prop, which costs about $600 more. A scenario where you wuld lose oil pressure, and prop control right after that, would be a complete disaster, as the engine would spool up so fast (the MT blades have bvery little inertia). The different style prop would remove that possibility, but I suspect it would weigh a bit more. > 3) If received unassembled, can any prop shop figure it out or do certain > ones specialize in the MT ? (Who might serve Colorado ?) Go to the MT website and look under distributors for an assembly shop in your area -- there is one in the Broomfield CO area. > 4) Is the MT spinner metal... can be polished ?? Nope -- composite. They will paint the prop & spinner any color you want for $150 extra. > > Thanks, John Meyers Golden CO > > Cheers! Mark I made the switch this weekend from my Hartzell 2 blade to the MT 3 blade and have performed some initial performance comparisons. I have accurately and repeatably documented my 2 blades performance at 10,000 feet, full throttle and 2100 RPM leaned 50 rich of peak. What I had at 10K was MP 21.3 WOT, 2100 RPM, 11.7 GPH , and 204-205 knots. With the 3 blade MT I now have MP 21.3 WOT, 2100 RPM, 11.7 GPH, and 200-201 knots. I think I can confidently say the MT is slower in cruise by about 3-5 knots. Also acceleration on takeoff, while still breathtaking, is not as strong as before. This is just a subjective comment done by feel. Climb rate seems about the same, but who knows, I just know it still puts the RV-8s to shame. Deceleration actually seems better with the MT, possibly because it is flattening out more. I like deceleration as much I like to go fast. Now for the really good news. I'll just sum it up with two words, VERY SMOOTH. Its like a different airplane, I think I put an electric motor on the front. It is smooth across the power band, exactly what I was looking for. The MT 3 blade spinner is approximately 3/16 closer to the cowl than the 2 blade spinner, but thankfully I set my spinner gape at about 3/8 to the 2 blade spinner, so my gap is now about half what it was but it looks real good, maybe even better. The new MT spinner complements the lines of the aircraft nicely, very similar to the Hartzell spinner in shape. This was a bolt off, bolt on mode, very simple. Thanks Mark for making it all possible. Greg Nelson N144X GlacierGreg neglected one nice thing about the MT, the spinner is finished, cut outs done, a real bolt on affair. It rocks. Best Howard Greg, > > Did you notice any significant differences in handling due to less weight on the nose? > > How about noise levels? Are the shorter blades more quiet at a given rpm? > > Dave Overall weights are about the same, but the rotational energy in the blades is far less (lighter blades), so you feel a bit less 'swing' about the yaw axis when making pitch changes. Noise levels are less (subjective opinion),... freq is different...it just sounds different on the ground too. Flyover observers tell of a different sound too -- very little blade noise (twang); mostly engine noise, and some whistling from the airframe. We measured a 2KT airspeed loss -- returnable with a slight RPM increase, if it makes any difference. I calculate about 1 1/2 minutes on a 600NM flight.... Cheers! Mark No difference in handling from the weight, but I did notice better deceleration when the power comes off for landing. I think the MT is going flatter than the Hartzell. It is now easier to control speed on final, and I can fly steeper with that big air brake up front. Noise in the pit is lower. My wife said it sounded different, but still sounded fast. She knows her airplane sounds! An airport friend said it sounded smoother, but still sounded like a Reno air racer. Cool. Like Mark pointed out, the rotational energy is less, the engine revs faster when pushing the power in, and on shut down there is no coasting to a stop, it just stops rotating right now. So far my starter/batteries have no trouble turning it over, not yet anyway. Speed vrs comfort. I'll arrive 3 minutes later after flying for 400 miles, but more refreshed due to the more comfortable cockpit environment. Good trade. Mark said my fuel flow sounded high, I don't think so relative to the speed of the ship. I have 10 to 1, ported etc so I'm sure I make more power at a given setting with WOT than a stock set up. I also have electronic ignition so that should lower the burn. I don't know. I can tell you I burn exactly 1 gall per hour less in side by side tests with another rocket who has a stock engine and we both lean to 50 rich. I'll be about 1 inch less manifold in formation with him. Incidentally when we do that my EGT is almost 100 lower than his, 1250 vrs 1350. We are talking about the 2100 square power settings here. That is the electronic ignition kicking in, or I have less drag or both. I can also set the same power setting and go 10 knots faster than his ship. We have flown side by side for 2 hours, then fill the tanks again, and I'll pump about 2 less. He also runs the MT prop, and all of the above comparisons was with my 2 blade, so some of the advantage was right there in the prop, but that still leaves me with a 5-7 knot advantage. Humm. Now that I think about it, we may be running closer on the fuel and power etc now that I am 3-5 slower. That remains to be determined with more side by side testing. Greg Guys Well I finally got rid of enough snow to enable me to get off the grass strip today and test the MT prop. I like it, I like it a lot. As many of you know I had a two blade Hartzell on this HRII before and a three blade Hartzell on the F1. With the two blade there was this annoying “thump” in the airplane, enough that my lower instrument panel used to vibrate and passengers could see my wing tips move. This is now gone! The prop spools up faster and when you push the throttle forward the plane accelerates noticeably faster than with the two blade. Also the plane is much quieter; I noticed this, as did a friend on the ground. It feels like a turbine, the way is speeds up and sounds. With low ceilings and no wheel pants I have no idea regarding any changes in top speed. I would gladly give up some top speed to achieve the smoothness that I feel with this prop. I was very happy with the three blade Hartzell; it was not quite as smooth but pulled at least as well as this MT. The main disadvantage with the three blade Hartzell is the added weight. This is still acceptable on the F1 but not on my HRII, due to the aft location of the main wheels on the HRII. This particular MT prop is the aerobatic model and it is kind of cool how it starts. The blades fail in the coarse position and until you have enough oil pressure to cycle the prop they stay that way, sort of lugging the engine for a few seconds until you see/feel the blade angle change. Then it smoothes right out, way cool…. If someone was working on a fixed budget when building a new rocket I would recommend cutting corners on the panel and going with the MT prop.Tom Martin Fairlea Field F1 builders Well I finally have some proper data for my new MT prop. I am 0.5 knots slower than I was with the Hartzell two blade. I think we can take lower speeds off the list of reasons to not buy a MT. Since first flying my HRII three years ago I have had my #5 cylinder run consistently hotter than the other cylinders. On this particular rocket I have the oil cooler mounted behind #5 and I blamed that for the problem, in that the oil cooler was taking too much air. This is only partly correct. The solution to my problem was a tip that I got from the Indy guys. Tom Utterbach had a hot #2 cylinder and tried many things to solve the problem. If you look at the forward face of the #2 cylinder, and the aft face of #5 you will note that the cooling fins are cut flat to the cylinder immediately inboard of the baffle mounting bolt hole. This hole is located under the injector on these jugs. The simple solution is to mount a spacer in the baffles between the cylinder and the baffles at this bolt location. I used a 3/16” piece of aluminium about an inch and a half long. This will allow more air to circulate around that side of the cylinder. I have lowered the temp of this cylinder at least 20 degrees, which brings it more into line with the other cylinders. I would suggest for those of you that are installing baffles that you make this mod. If your baffles are complete, fly the plane and check cylinder temps. It may not be necessary for your engine installation. I would also recommend not fastening the oil cooler directly to the baffles as I have on this rocket. It was an experiment on my part, as it is an easier installation, but I have had to make some repairs to the baffles, on two occasions, due to the added loads. I have not seen these cracks on my planes that had the oil cooler mounted on the engine mount I hope to see you guys in
The spinner drawing from MT shows the rear edge of the spinner 3.346" forward of |