Bill Tews Tips

SNIP I think that I can get a little more speed. I will try the aileron thing since I am going to have to adjust the hinge about 3/16" anyway to get the proper alignement with tips. Jack #70 SNIP All the recent aileron comments made me go and check the alignment of mine. I am busy trimming and rigging all of the wing stuff this week anyway. I was just getting ready to floxpoxy the left wingtip (from Van's) which had to be split to correct a nasty droop at the trailing edge when I read about the aileron droop giving a speed increase. Anyway I checked my ailerons and found them to be about 3/16 low at the leading edge. WHAAATTTT???? How can this be? I spent about a month checking and rechecking the @#$%ing alignment while building the wings. Everything is perfectly aligned along the entire wing trailing edge (except the wingtip warp mentioned above) and the flaps are nice and even with the belly skin. So, I pulled a wingtip off and checked the tooling hole alignment and this is what I found. With the tooling holes aligned perfectly, my aileron leading edge seems to be too low. When the aileron is drooped by turning the rod end about 2 turns, the bottom skin/leading edge seem to be in good alignment, but the tooling holes are WAY off. Raising the entire aileron by 3/16" would screw up the top skin, so I don't see that it is a simple building error. Is this the normal? Opinions? Don't forget, I'm using brand V parts. I don't know if F-1 parts are different in this area. Vince

Vince Using the tooling holes works, sometimes. I have two thin pieces of wood that I slide over the trailing edge of the aileron. I put a clamp on the end of them and then I line the aileron up so that it lines up with the top and bottom skin, centred between these two sticks. The sticks simulate what the air sees. If if does not line up then the brackets are in the wrong place. One of my f1 wings needed to have the holes in the aileron bracket slotted a bit to bring things into alignment. The next step is to line up the flaps with the ailerons and the wing tips with the ailerons and flaps. I had a bit of a problem with one flap as the tooling holes on the flap brace were not in the correct spot. That flap ended up a tiny bit high, but it flies well. Tom

My ailerons front edge is about 3/16" high at the tips and about 1/8" high at the flaps. Lui told me his were the same way so he sloted the holes to get the the correct highth and then drilled a third hole between the two sloted holes to lock them in place. This sounded like a good idea to me and that what I am going to do when it cools off a little bit. At the same time I am goint to readjust them to have a slight droop with no pressure on them and to be even with all the slop removed in an upward possition. Jack #70

The tooling holes are not correct. Marl told me to use only the holes aft of the spar and that changed the alignment quite a bit. Stick to Tom Martins advice. He knows.

Since this isn't my first RV either, I guess I should have known better than to go with Brand V dimensions when putting it all together prior to putting the wings on the fuselage. Hmmmmm, I guess the bottom line to this is that I should have skipped drilling the aileron brackets until the wings were installed! Haste makes waste.... but indecision never finishes an airplane! I used Van's wing template, wood strips, steel rulers, eyeballs, and the blueprints to decide where to mount the control surfaces. I'd say that it was the Van's airfoil template that caused my problem as it seems to hold the aileron TE down too far. That causes the LE to be too high. But when everything is on the fuselage, then the LE is too low when aligned with the flaps, and with the tips installed. YMMV. I suppose that it's easy enough to fix this by moving the aileron bracket. It will possibly make the top aileron skin bump up into the airstream though. Guess I'll have to take a hard look at that too. OTOH, I seem to recall that some airplanes have control surfaces that are purposely built thicker than the rest of the airfoil so that airflow reattaches. Makes my head hurt just thinking about it. It will be interesting to see how Van's prepunched RV-7 does in this area. There's one of these in my shop. The QB fuselage should be here this fall. I'm also gonna go look at 2 RV-8s and an RV-6 at my home airport next time I'm out there. Curiosity compels me. Woooo heeeeeeee, it's always something! :-) Vince

I have to speak up here, because the latest thread makes it sound like an aileron trim is a waste of time in a rocket. I respectfully disagree, I'm sure it's a matter of preference but in my opinion it is a must have item in a high performance aircraft like the rocket. Yes the ailerons are very light, and yes you can balance about every 15 minutes with fuel. I flew my ship this way, no aileron trim, for about 25 hours and it drove me nuts. The ship was constantly trying to roll left or right, one way or the other depending on were the fuel was at the time, anytime you let go of the stick. I like to trim hands off, and keep a very light grip on the stick, and when its always trying to turn you can't do that. Look down at your map or approach chart, roll wings level, tune the radio, roll wings level. I added an electric trim and wow, what a difference, really brings out the nice handling qualities of the ship. The ship is that much easier to fly with the trim. You do have to remember to change tanks once it becomes second nature to just blip blip the trim to hands free every once in a while but that has also become second nature. For me no trim was a big deal and I wish I had not listened to the experts who told me the rocket would not need it, as it would have been much easier to install the trim during the building process rather than retrofit the add in after I was already flying. No disrespect to those who don't want or have aileron trim, I just thought some builders out there might appreciate a different perspective on this. Greg Nelson N144X

Question about the wing bolts. As far as getting the bolts through the > spar, how tight are the bolts suppose to be when inserting them? i.e.. are > you suppose to be able to push the bolt in by hand, or are they tapped > lightly, or do you get out the Luis malletized...Ha > > It looks like mine are extremely tight and I think need a big persuader > tool to get the bolts all the way through. Don't want to do that. Is this > a job for a reamer tool? If so, what actual size do I need and where do I > buy this reamer tool(s)? >

Yes. Luis will enjoy putting the wing bolts in...!! Please get the a .374 reamer, and run it through the spars and splice plates. Don't worry too much about the sheet metal bulkhead...it can't slow you down too much. I think the problem is the plating on the splice plates, really. Marcus used our 4X rivet gun with a flat set when necessary...saved his arm a LOT! Be sure to use a back-up weight on the opposing side, or clamp the splice plates well. Cheers Mark

Luis - The bolts should be snug enough that you cannot slide them in by hand but a gentle tap with a soft face hammer will seat them. Try and put a bolt in the splice plate before installing on the plane to make sure that the anodizing has not filled the holes. Start first by installing hardware 3/8" bolts in most of the holes, then remove them one at a time and replace with the correct bolts. Be careful when using a reamer to keep it straight or it will male oblong holes. As always be sure to put a small dab of anti seize on the bolts before insertion. Should you ever have to remove the bolts you will be glad you did. Do not get it on the threads or it will change the torque value. Tom

Yes, the plating does make the ID of the spar bolt holes a bit too small. I would suggest mic'ing some hardware store bolts making sure they are undersize to your existing holes, or possibly have some ground by a machine shop that are .001-.002 undersize. Then, put the wings on with a few of those bolts and carefully ream. I highly recommend that all the reaming is done in assembly, not separately. Make sure you get a hand reamer, not a chucking reamer. You may have to get creative on the lower bolts as there isn't much room to turn the handle with a tap wrench. A NAS close-tolerance bolt is designed for an interference fit, and in AC43 it says that NAS bolts should be a hammer-fit. Using a rivet gun to drive them in as Mark points out makes installing them a breeze, provided you do the reaming and get the proper fit. Regards, Bob #80

Earlier kits had the wrong size holes (.369" approx). I could'nt pound a bolt thru mine with any hammer I own. I used a .372 reamer I had and it did a fantastic job. The bolts now tap in and out with a small hammer. FWIW, My wings were never fitted at the factory. The inboard ends were a little too long and prevented me from getting the bolts and plates to assemble. It cost me a new doubler plate as I ruined one with the reamer trying to push it thru the first hole. This illuminated the fitup problem. I removed about .020" from the ends of one wing and then it all came together well. Later kits don't have this problem. I had to ream the fuselage former holes as well. couldn't get a big enuf hammer in there to pound the bolts thru the too small holes. Just a wimp I guess. Good luck. I'm a firm believer of assembling the wings together while off the ship to make sure this stuff fits. It's a real pain to do while on knees inside the fuse. Warmest regards, Bob Gross

Mark This was said to apply to "earlier kits", can you tell us which, or is it all? Dave Bockelman #046

If you are referring to reaming the splice plates, all are plated after machiniing, so I would expect all to require the reaming too. As Bob Gross mentioned, it is a good idea to test assemble the wings as a unit on the shop floor, complete with splice plates, prior to mounting them to the fuselage. This will assure that the close tolerance holes are the correct size -- not so easy once the wings are fitted to the fuse. Cheers Mark

I second the use of the rivet gun to drive those tight fitting bolts into postion. I greased mine and reamed the holes to .374 and still needed the rivet gun to drive them home. Yes, a giant hammer will work, but who wants to swing a hammer in those tight confines. Will scratch your pretty paint too. BTW, disassembly is the reverse... rivet gun from the opposite side. What are the nuts for? Certainly not to keep those driven bolts in the hole. This seems like a very good spot to save weight by using shear nuts or Ti nuts. Mark, what say ye? OK for lightweight nuts here? Vince

I've had one builder come up with a problem that I can't figure out: either
how it happened, or how to fix it!

The tips were fitted as normal, but when re-attached they didn't fit
correctly at the trailing edge.

If you'll recall, the tips have a notation written on them to install ribs at
the front & aft spar locations. These ribs are actually extensions of the
spar, more or less, and serve to strengthen the top surface against
compression loads. I recommend that builders fabricate these ribs from house
insulation foam, and cover at least one side with 2 layers of 9 oz cloth. I
suspect this builder did this procedure, but didn't attach the ribs in place
on the wing while the resin set up. I suspect the tips took a different shape
than required for a good fit.

So: when you lay up the cloth onto the ribs inside the wingtips (be sure to
make a 2" flange onto the inside of the tip), cleco the tips into position ON
THE WING while the resin sets up. Make sure the TE lines up properly, too.

Cheers
Mark

Billy, it acts as a stiffener, as opposed to a fixed rib. If you view it as a rib cut in the middle horizontally, each half is attached (in my case riveted) to the wingtip on the upper and lower surface, but attached to itself at only one end. That allows some flex, but not totally stiff as a solid, fixed rib would be. We installed two in each wingtip, equally spaced, because of the thinness of the material. Art Chard is a Master at solving this type problem, and this was his fix to possible compression of the wingtip at high speeds. Whether we need it or not is questionable, but I have seen no distortion in the wingtip at any speed with it. Interestingly, Mark's first question when he saw Blackjack for the first time was whether or not the wingtip started to distort at higher speeds. Jim

Bob, we installed two floating ribs parallel to the wing inside each wingtip. If you attach the upper and lower half of the rib together at the outboard end, and attach each rib half to the respective upper and lower portion of the wing tip, it floats,i.e., it still gives until you attach it to the aircraft wing. Stop the inside of both upper and lower rib halves prior to getting to the part of the wing tip that attaches to the wing. Now when attached to the wing, the tip is resistant to compression. These floating ribs act more as a stiffener than a solid rib. I understand the newer wingtips have interior molded ribs that do the same thing. I think this is important if you don't have the newer tip. If this doesn't make sense I will try and find an old picture, or you can call me at (406) 755-1829. Jim

Where can you get the reamer(s) for the wing spar? I've tried the sites I have for tools, but no joy... Thanks, Bob

When installing flap brace do NOT attach the brace to the wing skin as it can
not be done and have the flap line up with the top wing skin. Clamp the flap in
place at each end while the brace is free floating and confirm that the flap
meets the top and bottom skin properly. Now drill through the skin, brace and
hinge at both ends. You may at this point note that the factory holes between
the lower skin and the brace do not line up. Finish drilling every third hole
from the center out with a partner backing up the hinge. Worked well for me. I
found it necessary to tighten the forward flap radius with 1 1/4" tubing taped
to the front edge and twisted. Mark said I should "smunch" this front edge but
my "smuncher" had a tooth missing.Blue skiesBob W

I'm trying to figure out the wiring for the flap switch, and I noticed that the flight manual mentions a 20 degree
flap setting. Is this ever used, or in operation, do you always have the flaps up, or full down? Is a normal
takeoff made with flaps up? Or do you sometimes use 1/2 flaps, or full flaps? Thanks, Scott Roth

Hey Scott: Yes, you will use a 1/2 flap setting most of the time. Full flaps seem to be used for an amazingly
steep approach, or for departing from a mud strip. I have been in both scenarios... The prop is a very effective
brake on this ship. Cheers Mark

I put three or four gallons in each tank and tried to get it all out in order to clean them. I later was able to put
25.5 gal in the left tank and 26 gal in the right. I am using the EI fuel gage. I have tried to calibrate the left side
three times and the right once. The sender will register full at around 22 gal. so there is no calabration past that
point. The left and right react diffrent because the location is diffrent. So far the in flight reading have been
very poor. Thankfully the EI fuel flow is working very well. I really wanted good fuel level readings and have not
given up yet, but it dosen't look to promising. Jack #70

Jack I am using the VM1000 and the fuel flow recorded has been quite accurate to date. My tanks have the
standard senders that came as supplied and I am using the old reliable Van's style guages. They seem to be
recording the fuel levels with as much accuracy as you can get with that style of guage, certainly adequate
when you back them up with a good fuel flow device. (and a watch) Tom Martin

I don't there's much hope to get accurate readings from a float-type gauge, due to the wing dihedral, and the
sender being at the root. The capacitance plate-type senders I understand work better, but they require major
surgery to the already-built F1 tanks to install. And they have their drawbacks also. I hear from local
automotive engineer friends that they are working on ultrasonic senders to deal with irregular-shaped tanks in
cars, I imagine when these sensors are available in a few years they could be adapted for our airplanes. Float
senders are accurate when the tanks are near empty. Tom, where is your flowscan sensor located? Regards,
Bob #80

I put my fuel flow sender between the mech. pump and the injection, attached to the lower engine mount by
an alumn. bracket and two adel clamps. I get a fairly stright shot at it on each side and it has been reading a
little over a gallon high on a tank of gas. After some long trip I may try to adj. the 'K' factor but as is it's pretty
good. I have been trying to adjust for a reliable reading on the fuel gage for 1/2 and 1/4 full but so far no
success. Jack #70

Bob the Summit Racing guys have the gages that will work !!If Mark F doesn`t get back to you ,let me know
and I`ll dig thru the reciepts and find it for you. Bill A

G'day Bob & Bob, I had previously checked the range on my fuel senders - empty is about 240 ohms & full is
about 30 ohms. I have my ASI marked in knots as it is a requirement down here and the ranges I have are -
White arc 47 to 95 knots,
Green arc 60 to 160 knots
Yellow arc 160 to 220 knots
Red line is 220 knots
The green arc could probably start a little lower, but your're flying a lead sled at that speed anyway!!!
YMMV Cheers, Ron Graham (#105)

Sorry - I shouldn't try to do this from memory. The redline/top of the yellow is 240 knots. Cheers, Ron Graham (#105)

They are Stewart Warner senders and as
mentioned are resistance type with the
resistance decreasing as fuel increases

I used the IE digital fuel gage and I am not happy at all, however, the problem is in the fuel senders and not
the gage. The sender is at full range when the tank is 3/4 full and the fuel quantity is not accurate unless you
maintain perfectly level for several minutes before looking for a reading. Also sense the senders are in different
locations so they do not react the same. Thankfully the fuel flow gage is very reliable. To sum it up get a good
fuel flow gage and save your money on fuel gage by using the cheaper dial gages. Jack #70

Mark, What size bolt do I put in the fuel tank attach fittings? The manual > shows AN3 to attach it to the
longerons, but.... AN4 to bolt them together? > That will work OK....use a castle nut, as this joint is the
same pivoting style as the rear spar attach....

Hey Guys, I want to point out here something here that I feel needs to be changed in the manual. On the RV's |
a few years back a change was made to the tank attach bracket to improve the chances survivability in an
accident. If you have the tank attach bracket bolted solidly to the fuse, and if the wing were bent back in an
accident (which it can, easily, trust me), the fuel tank will rip wide open at that spot. The solution was to slot
the bracket that attaches to the fuse and NOT torque the bolt tight so that if the wing LE there wants to pull
away from the fuse it can, yet the strength in the vertical axis is maintained. On the RV-8 they went so far as
to use a nutplate for an AN-4 bolt on the tank bracket, slot the fuse bracket, and use a drilled head bolt with
safety wire. I have personally seen first hand an off-field landing of an RV-8 where the tank pulled away from
the attach bracket on the right side after the gear legs sheared off and a wing dug into the dirt. !
Regards, Bob #80

Hey Bob: I'll put it in as an option for the builder to decide -- send me pics when you get to that stage! If any
of you other builders have ideas like this (or better photos than I took!), by all means send 'em in! Cheers Mark

Have a look at the attached please -- do any of you see a potential trouble
spot here? Sure is easy to make this style vent system as you build the
wings...

As I see it, the other system could save you about the amount of fuel in 2'
of 1/4" line...thxMark

I have heard this mentioned before. It looks simple and easy. Does it work in practice? I notice the vent is
faced toward the rear. Will this eliminate icing? Thx Bob W

Well, we're gonna try it! No, it faces fwd like the rest do. We'll come up with a nifty machined thingy if it works OK. Might add a loop or 2 at the Mk.2 Mod.1 version...
Mark

Mark--

I would be concerned about syphoning on a warm or hot day with the tanks full.
On a Glasair I had, several gallons would syphon out on the hangar floor on an
85+ deg day in MI if the tanks were full. I could not top off the tanks before
putting the plane back in the hangar in the summer. The Glasair used a vertical
loop similar to that used by Bob Gross but not quite as high.

When the time comes I'm going to look into a one-way vent valve as used by
Beech. It lets air in, but prevents air or fuel going out until the pressure
gets up to a couple? of pounds.

Yeah, I know the Glasair fuel tank is different, wing tip to wing tip, but it
sure gets hot here in the FL paradise. Jim

I have heard that with the vent facing forward it will ice up. The Glasair III has a 45% forward and a 1/8" hole in
the rear of the tube. Hole may be for ice. Bob W

Jim - Wicks sells a fuel check valve (PN CV-3/8). Is that the type you are considering? Perhpas if installed
in-line (and backwards) with the standard vertical loop it might reduce or eliminate incidence of overflow
from extreme (inverted) attitude changes while still allowing venting in high pressure situations.
What do you think? -- Bill

Well, you have a point there. The end of the vent line is at the highest point of the tank, with the ship in 3 pt
attitude. If to starts to vent due to expansion, it will, of course, push fuel out till it gets to a level below the
end of that line, same as it would with the Mk.1 system. Not much change there, methinks. It could be that
with a couple of loops, per Tom Martin, (Mk.2 Mod 1) it would vent a bit less...but not much. I wonder if
there is an altitude aspect to consider, ie: will I have to switch tanks after burning about 1-2 gal, as I do when
the line person fills the tanks to the top anyway. At 25GPH on takeoff, 1 gal goes out the pipes pretty
quickly.... I usually tell 'em to leave it about 1/2" below the bottom of the ring. Not much chance of venting
with this fill level. Cheers Mark

Be careful fellas. Anything over 1.5PSI is dangerous to the life of your tank. Mark

Mark - Andair's fuel check valve (Aircraft Spruce P/N 05-29555) is designed for use as a fuel tank vent valve
(among other things) - the break-out pressure is 0.4 to 0.7 PSI according to the Andair web site. Bill--

I see the Wicks valve you mentioned and it looks like it would work subject to
the breakout pressure listed of 0.5 lb. Don't know if that's quite enough or
not. I'll try and find out the b.o. pressure of the valve Beech uses and let
y'all know. Jim

Anybody know the vent system used by Piper or Cessna? Check valves etc? I'm not
aware that they use a standpipe arrangement and know that Beech does not. Their
systems work fine, are reliable and foolproof. This may be one of those times
when it would be best to follow the flow [pun intended]. Jim

Looks to me like all of the fuel above the vent fitting in the side of the tank will be pushed overboard by gravity.
If not, then once some event occurred to cause the fuel to complete the loop (like fuel expansion in the hot sun)
, then the siphoning action would cause all the fuel above the fitting to be siphoned out. I must be missing
something. Randy #95

How close is the outboard edge of the filler hole to the outboard end of the tank? Seems line you could get the
end of the vent line out a bit further than that and thus be higher that the filler neck and also be higher that
the highest point that the tank could be filled before overflow. At most it seems like you would only push a
|few ounces overboard before the level was below the end of the vent tube. Just wondering since I haven't even
touch the wings yet so have no personal experience with this fuel dumping phenomenon and incredibly bizarre
vent line routing excercise. scot

I've only had 17 engine failures in my pathetic 14000 hour career. Six were caused by the a fuel vent problem in
a Pitts S1. I take fuel tank vents VERY seriously. Stick with what is proven or be willing to pay a very, very high
price. (Still painting) Warmest regards, Bob Gross

Well, this is my thinking, from what's left of my brain.. I've seen all sorts of ships venting fuel -- even my own
on the ramp in PHX. I just don't fill it if it's gonna set for any length of time. If I'm blasting off immediately,
I worry less about it. For Bob Gross: At worst, it seems I'll lose what would be captured in that short length
of line. I doubt the system could fail, unless my buddies the mud daubers find the vents before I can get a
piece of safety wire in 'em. The end of the line in the tank is at the same place as would normally, and the
inlet under the fuse is moved outboard about 4". And, the loop is gone....it does have a larger tendency
towards siphoning, but it cannot pull fuel below the level of the outboard end of the tub in the tank. Same as
the Mk.1 system in this regard. It sounds safe, and until some genius says it won't work because....it's
Tuesday.... or some other good reason, I'm gonna try it. It sure is simple. All it has to do is let air in, and not
let too much fuel out... Have any of you fellas seen the routing in say, a C210 or C182? Cheers mark

Why not vent the tank from the outboard end? Given the dihedral, the upper, outboard corner of the tank is
usually above the fuel level. If I'm missing something obvious please let me know. I normally have at least 3
stupid ideas a day and I haven't met my quota today:) Danny Melnik

Mark - the new Aircraft Spruce catalog (2003) p. 155 list several models of Andair check valves - one style has
a bleed which "allows shuttle to weep off pressure in the event of a blocked line". I'll send Andair an e-mail as
see if the company can provide more information on how the "bleed" works. As for sticking --- while a
possibility, the probability that (with one for each tank) both would stick at the same time or the one that
sticks is that on your last remaining tank is pretty remote. Lots of other failure modes in these magnificent
toys to put one in the cow pasture. Regards, Bil

I am not sure about this wing tip venting idea. Yes there is a dihedral in the wing but a LOT of my flying is not
wings level. It does not take much of a turn to put the wing tip lower than the fuse. If you compond that with
an unco-ordinated turn, ie a slip or skid while looking down, and there goes some fuel, right out the wing tip.

I am have had no problems with the current fuel vent system on three previous planes. I rarely leave it parked
outside with full tanks, but there are lots of planes that vent a bit of fuel with the tanks full, I know a certain
Pitts that just pisses fuel out when full.... Tom Martinl

Fuel tank vents on Cessna/Piper single engine aircraft are taken from just inside the fuel filler neck, run along
the upper outboard edge of the tank just under the skin, then vent through the bottom wing skin just outboard
of the tank - no non-return valves, no loops, just an open line. They all vent fuel onto the ground on a warm
day with full tanks. Regards, Ron Graham, Oz. (#106)

I have the check valve between the tip tanks and the mains so mine will actually vent from the tips. However,
I also ran the main tank vent up into the cockpit and back into the wing root exiting through the bottom alum
fairing just in front of the spar. I am considering putting a on/off valve in the cockpit to force fuel to come
from the tip tank in to the main as it is not quite down hill. I think the loop is too low and you are going to
loose at least a gallon or two of fuel when the tank is full. Take the front view of the F1 drawing and draw
a horz. line fron the top of the wing root to the tip and there is a lot of tank space above the line. Thats what
I did for the tip tanks and why I don't think I have enough down hill run. Jack #70

FWIW I checked with Beech tech on the one-way vent valve as used on the C33A,
p/n 50-380170-11. They give the breakout pressure at 1" +- 1/2" of water.
Converting per Machinery's Handbook gives 1" of water equal to 0.036 psi. I find
it hard to believe the pressure is that low.

I like the idea of Denny and Tom to run the vent line out near the tip. It's
simple, no residual fuel in the vent line and fuel and fumes are kept away from
the cockpit. A check valve in the line would reduce syphoning on a hot day.

Mark-- A dumb thought for the morning. Have you calculated/ estimated the
amount of vacuum required to pull fuel out of the bottom of the loops and back
to the tank to enable normal venting?Jim

Why not vent the tank from the outboard end? Given the dihedral, the upper, > outboard corner of the tank is
usually above the fuel level. > This would work too, but the plumbing wouldn't be easy: you would have to get
at the fitting to attach the vent line to it, and there's very little room there. I discussed this setup with the CZ
boys, but we couldn't figure out how to do it quickly and easily. A nearby inspection panel would be the ticket,
but we didn't want to drill a big hole in the LE skin. Project cancelled. Attaching the line at the root and running
it out to the tip, like Tom Hall has done, would effectively do the same thing. Some of the plastic lines &
fittings would be OK, as long as they were fuel proof. Cheers Mark

Mark and all, the only trouble I see with this set up would be icing blocking the vent. Stay out of clouds and the
stuff that falls from them and you will be OK. This is not always possible even in a VFR only airplane. The
traditional out let location is shielded from ice by the cowl exit, and is warmed by the engine, thus ice is less
likely. Cessna hides their vent behind the lift strut. It does not take much to block the ice, as ice forms on
anything that sees ram pressure, like leading edges and things that stick out into the air. If you go with that
set up, some sort of alternate vent for at least one of the tanks would be a good idea. Maybe a T fitting to a
check valve so that if the pump tries to suck fuel from the tank, and the vent is blocked, the check valve
would open and let air in. Greg Nelson

Yes, and this would explain the #30 hole drilled in the back side of some vents. I guess I'd better incorporate
that idea, if I'm gonna have those parts sticking out in the breeze. Cheers Mark

I just looked at another Glasair III and they have a 3/8" vent tube cut at a 45 degree facing forward and a #30
hole slightly above the top of the 45 at the rear. Thats for me. Blue skies Bob W

I'm sorry guys---I'm really trying to lay low, but I just have to ask. Why in the world would you want to deviate
from a time proven system in an area that can BUST your Ass? I have never smelled gas, seen gas vent or
pissed fuel that I am aware of from the venting system that I used on my F-1 and have observed on most of
the 3000 RVs currently flying. I used the standard inside fuselage loop with tank vents located conveniently
behind the lower cowling, close to the exhaust flow just like my RV-4 and RV-6. I take a small piece of
fiberglass screen, put that around the protruding vent and secure it with a small black nylon tie-wrap to
keep Mark's dreaded Dabbers out. It has worked great for over 100 hours with no fuel in the cockpit, nor smell,
and on one occasion turned the black airplane into a bonified ice cube. In cases such as this the KISS principle
is pretty important. Check valves fail. Jim†

Does anyone have the list of parts that it takes to go from an aluminum tube fitting to a plastic line?

A couple of methods will work here:

Simplest would be to use a 2" length of vacuum line to join the 2
There is a fitting made to join the two -- also made from plastic. A bulkhead connector for the plastic line would also work...Carry on!† Mark

Randy, I used a piece of 1/4" id rubber hose about 4-5" long†slipped over the hose and the alum. tubing for my pitot connection where it changes from the aluminum to poly tube.† Works just fine. Regards, Bob

Thanks.  I think that's what I'm going to do.  In retrospect, I don't see a need 
for fancy (heavy) fittings to do this. Randy #95

New Builder question (yeah again) Is there anything wrong with just using the nylo flow tubing in the wing? Vince

you have to have some length of aluminum tube in there if you have a heated pitot. IIRC a heated pitot operates somewhere in the 300-400 degree range. I don't think that would bode well on a piece of polyflo that's buried in the wing and hard to get to if its connected directly to the probe and melts. Regards, Bob

Listers
I have my wings off now, but am trying to plan and do fuselage wiring --† for pitot static line(s)†from Left wing, has anyone successfully run pitot tubing or coaxes over spar under fairing in root/fairing area? †Am told there will be very little room there.†

If not feasible, how did you run yours? Thanks Dave Bockelman 046

Yes I have done that, I use flexible plastic ºî tubing. †It is the same stuff that trucks use for air brakes. †I put a one foot piece of aluminium †tube on my heated pitot tube and then run this plastic tubing all the way to the airspeed indicator with no other fittings required.

Tom Martin Fairlea Field

I did the same as Tom, including the foot of AL tubing near the heated PITO, then plastic line.† Truck Brake line tubing is probably over kill unless you go Mach 18,†I just used†the stuff Aircraft spruce sells. Greg Nelson†

guess I forgot to mention that the truck air brake tubing is really cheap, light, available everywhere and ten thousand years from now will probably be the only part of the airplane left for archaeologists to contemplate†

Tom Martin Fairlea Field

pulled my tanks to pressure test them to 8000 psi. Before I put them back in, I ran the Pitot tubing behind the tanks along the FWD spar face.

Feeling a bit kookey my self you know.....Warmest Regards, Bob Gross I vote for this solution, there's a lot of room behind the tanks and it makes getting past the spareasy as there are already holes in the spar that you can get your hand through out in the areaof the petot. Another thing you can do if you don't want to pull the tanks is to put a leading edgelanding light in the cell just past the tank. this would give you enough room to drill and put abushing in the rib and slide a piece of tubing behind the tank. I put my landing light there inorder to plumb the tip tanks. If you pull the tanks, a couple of 2" or 3" strips of alum. will makeit much easer to slide the tanks back into place.Jack #70

Mark, A friend recently explained to me that the RV-4/HR has a piece of angle (2) that is used as a gusset that bolts to the forward upper splice plate and the keel beams. Is this required or necessary for the F1? Thanks, Scott

_Yes, and if you look on P469 & 470 of V2.23 you will see the description > and installation. The parts are F-043, and are supplied in the kit. Don't leave any parts out of your airplane! Cheers Mark