Javron false boot cowl

[Scott A]

What are you doing at the tops of the false boot cowls - Piper drawing 12818 shows that both the left straight one and the right angled have folded over seams. The left is ½ inch I think and the right 3/8 inch. All the interior panels come folded over as called out but I suspect these are not because of the variation in 3/8 channel from cub to cub.

Are you folding? Just cutting off straight?

What about attachment across the tops. On many, on the door side, I see screws but there is nothing to put them into except the tube and that is not an option really. The door channel is tight against the tube so no way to get a screw into just the channel/frame.

Lemme see if I can finally make a photo happen..

[DENNY]

It is a bit late but before you do any more metal work on the nose I would put the fuselage on gear and hang an engine or box of equal weight off the nose. I built a nice 3 part boot cowl while I had my engine out to replace the cam, once I hung the engine the frame flexed and the bottom gingerbread holes did not quite line up. I managed to get them drilled out but it was a pain. If I remember correctly my stock cub does not have a fold on the false cowl panel.
DENNY

[Scott A]

Thanks for the info Denny. I'll have to put it on stands soon and remove the front rotisserie to mess with the boot cowl/firewall so I will see about hanging some weight out there.

[fishhook]

Door side I am welding a channel on for nutplates, most cubs I see dont have any screws there or they are screwed into the door channel. Window side doing the same, I am terminating the false bootcowl before the window. Also I have the full slider so it wall actually be the stock height, I will have some exposed steel but no big deal its a cub. Don't screw it into the tubes, I see that quite often and its a hackjob. Denny I built my bootcowl on the rotator, my friends all said they didn't have fitment issues, then again I think they all oversize the holes and hung the engine after putting the cowl on.

[fishhook]

Also I plan on putting a small bend at the top edges of the false boot cowl panels and using the .020 thick butyl tape they sell as a sealant.

[acroeric]

Following along as I am at the exact same point with mine. I actually thought about leaving it off all together and just covering that area. I can not see anything I'd need to get to behind it. I'm running the Dakota fuel selector and it is a little more forward than the originals. I elected to build a Ti firewall as well. My boot cowl was damaged in transit. Getting the angle just right where the firewall interfaces with the boot cowl has resulted in an impressive scrap pile. Getting there but slowly.

[stewartb]

Why do you need it?

Removable boot cowl sides are a great addition if you plan to have any glass panel components!

[skywagon8a]

If you brake an angle inward along that edge, it will stiffen the edge minimizing or eliminating the need for any fastener. Another thing to consider is to ask why the false boot cowl is there at all? Remember, when Piper built these planes the only fabric which was used was grade A cotton. When applied using the CAA's minimum suggested dope coats, it was expected the airplane needed to be recovered every 4 or 5 years. They didn't want to remove the engine, windshield and boot cowl just to replace the fabric. So, the false boot cowl. Bingo, pull it and replace the fabric. You're flying less than a week later. The time consumer was waiting for the dope to dry.

[acroeric]

I can see that would be helpful. My G3X comes out with 4 screws and gives me a pretty large area to work if needed. My boot cowl is going to be in 3 pieces but the piece shown in the original post is the one I was considering leaving out. Looks like you just made your boot cowl to go all the way back to that former and eliminated the fairing shown by the OP. Pretty neat idea.

[Steve Pierce]

Piper used 3003 soft aluminum and bent the end over itself. I use 2024T-3 and trim to fit and put a slight break on the edge.

[stewartb]

I can see that would be helpful. My G3X comes out with 4 screws and gives me a pretty large area to work if needed. My boot cowl is going to be in 3 pieces but the piece shown in the original post is the one I was considering leaving out. Looks like you just made your boot cowl to go all the way back to that former and eliminated the fairing shown by the OP. Pretty neat idea.

I’ve added a couple of items that required adding pins to the two major connectors. Removing my left side boot cowl makes it a lot easier. It’s still tight in there but through the panel? That would be impossible in my plane. Adding the AOA line to the ADHRS was through a removable breaker panel.

[KJC]

A suggestion only but you may be putting the cart before the horse on this a bit.

Maybe a better order…..

Fuel Lines and Valve
Jack Screw and Trim Cables
Stringers
Floor Boards Brakes
Pannel and Wiring

Youll figure out the rest.

[tempdoug]

Why do you need it?

Removable boot cowl sides are a great addition if you plan to have any glass panel components!

somewhere on this website theres a good thread about making this style of boot cowl. it was talked about a while back.

[Scott A]

Thanks for all the great responses and ideas!

Not using them at all makes a lot of sense. I will keep them though because I added the metal belly pan under the entire main floor area and want to keep the overlap on the bottom - boot cowl overlaps the false boot, the false boot overlaps the belly pan.

I will add the slight break along the aft edge as shown on the Piper drawing 12818 and slight break along the top edge with the seal tape. I may weld in small angle so I can get two anchor nuts also, just give me a warm fuzzy if something was pulling it in tight with a seal in there.

I guess I could still run the fabric under them as if they are not there to keep water out - hmm - but extra weight

@KJC, how I ended up here (it will be helpful when I post a project thread) - Jackscrew and electric trim already in, stringer already on or fitted and removed (in the way for some welds), floorboards and brakes already in and out (just the master cylinders, no lines yet), waiting on my new fuel valve so decided to wait on the fuel lines - I wanted to minimize the putting stuff in and taking it out, if the floorboards and pedals are in I would not be able to back drill or add anchor nuts under the floor. I decided having the boot cowl all fit will show me exactly what space I have for the forward fuel lines etc. Also I saw some where the fwd fuel lines ended up right behind anchor nuts, this way I can route them to miss from the get go (easy enough to move but as someone pointed out in another thread if the fuel line is right behind anchor nut someday down the road someone will put a long screw in and hit the line). So anyway throw this on and off so I can put the floorboards, pedals, cables etc in and not take back out. I'll start a progress thread so my blathering and rambling can go in there.

Again thanks to all for any and all input!

[skywagon8a]

I will add the slight break along the aft edge as shown on the Piper drawing 12818 and slight break along the top edge with the seal tape. I may weld in small angle so I can get two anchor nuts also, just give me a warm fuzzy if something was pulling it in tight with a seal in there.

Remember your lower door overlaps this top edge you are addressing.

[Scott A]

thanks for the heads up.

Remember your lower door overlaps this top edge you are addressing.

[Sam D]

These are great for putting a slight bend on the edge.

[Scott A]

Thanks Sam.. and you're welcome, LOL.. I posted here instead of pestering you with another PM

[JTA]

Exactly what Steve P says. Piper used thin soft aluminum that benefited from the edge being folded over on itself. I used 2024 and broke the edge. 2024 will break in half at the bend line if you fold in back on itself i found this out making up new false boot pieces so i have been right where you are at. As far as attaching... I followed what Piper did EXEPT I did not put any screws into any tubes (structure). Also, because i didn't know any better I made up all new sheet metal for the whole plane before hanging the engine. I had no issues with fitment maybe because i used a new frame? Sounds like good advice to hang some weight or engine, the time it takes to make, fit and paint all these little pieces would be a real bummer if they didn't fit in the end.

[Steve Pierce]

Out of the 5 Super Cubs I have rebuilt that had never been a part the 1979 and the two 1982 Super Cubs had holes drilled in the tubes around the flip up window and door. None of the other Super Cubs I have worked on had this issue. The holes for the interior trim/welting was drilled in the u channel. All of them had the panel under the door screwed into the horizontal door tube. I weld tabs to this tube for Tinnerman clip nuts at rebuild.

[skywagon8a]

These are great for putting a slight bend on the edge.

Use caution when using this type of tool. It bends only that small piece of metal which it is grabbing at the time. The adjacent piece of metal is pulled to one side thus stretching the edge. The end result is likely to be the bend you want but with a slight curve. It is better to bend the whole bend with one action. Even if you have to improvise by clamping between a couple of pieces of wood or anything which will give you one long bend.

[Steve Pierce]

I use this edge rolling tool.

[Sam D]

Thanks Sam.. and you're welcome, LOL.. I posted here instead of pestering you with another PM

you’re a long way from wearing out your welcome!

[Scott A]

... as far as not using them at all, in another thread on here (that I have lost) wasn't it determined they came from the requirement to have 24 inches of non-combustable from the firewall back? Or was that still muddy? Of course experimental can do whatever (unless the DAR or FAA doesn't sign off).

[skywagon8a]

... as far as not using them at all, in another thread on here (that I have lost) wasn't it determined they came from the requirement to have 24 inches of non-combustable from the firewall back? Or was that still muddy? Of course experimental can do whatever (unless the DAR or FAA doesn't sign off).

CAM 3 Cowling 3.625(b)
24" is the correct answer.

[Gordon Misch]

Do you have a link for that? The pdf of CAM 3 I found is missing a couple pages and jumps form 3-587 to 3-630. Thanks - -


Edit: Found it as a download. Thanks. The Google hit on search term "CAM 3 Cowling 3.625(b)" was this: Airplane Airworthiness; Normal, Utility, And Acrobatic Categories

"3.625 Cowling.(a) Cowling shall be constructed and supported in such a manner as to be capable ofresisting all vibration, inertia, and air loads towhich it may normally be subjected. Provision shall be made to permit rapid and completedrainage of all portions of the cowling in allnormal ground and flight attitudes. Drainsshall not discharge in locations constituting afire hazard.(b) Cowling shall be constructed of fireresistant material. All portions of the airplanelying behind openings in the engine compartment cowling shall also be constructed of fireresistant materials for a distance of at least 24inches aft of such openings. Portions of cowling which are subjected to high temperaturesdue to proximity to exhaust system ports orexhaust gas impingement shall be constructedof fireproof material."