In progress, weight situation.

[gdkl]

In progress, weight situation.


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I am building a PA-11 replica with C-90-12F and I am ready to cover (Stewart System). I just weighted the complete fuselage, epoxy primed, completed instrument panel, inside paneling, control cables and trim system, seats, door and windows (no plexiglass yet) and no tail control panels installed. I came up with 210 lbs. My question is: Am I within acceptable limits at this stage of construction; my gross weight has been set and accepted at 1500 lbs.

Any comments on this subject will be appreciated.

 

[courierguy]

I can't give you specific numbers as to your PA-11, BUT several homebuilts have taught me to do WHATEVER you can to cut the weight, spend hours studying every thing, you have to get real anal about it!
A wide series of hole saws and a few uni-bits will help. Don't get into the mindset of "that'll take 3 hours and only save a few ounces", a low finished weight is as much a bragging point as top speed etc! Also, every time I see some little lightened detail on my homebuilt, that other builders of the same type overlooked or didn't think a big deal, it is very satisfying. You will NEVER regret all the extra time spent, and it may, like it did me, get you in the habit of looking at EVERYTHING with an eye as to how you get make it lighter, you ever notice those big flatbed truck trailers with the lightning holes in the frame rails?? I love those....

 

[gdkl]

In progress, weight situation

Thank you Courierguy for your words of wisdom. I will keep your philosophy in mind from now on.

I still would like opinions from Cub owners/builders as to the weight of my project for comparison and expected empty weight when completed.

GDKL

 

[StewartB]

I never weighed my project until it was airworthy. It served no purpose. I had no control over primary component weight and where optional equipment came into play I made my decisions about what to add and what not to. In the end there's nothing I wish I'd added and nothing I wish I'd left off. That's as good as I can do it.

I'm curious about PA-11 kits. Whose are you building?

Stewart

 

[gdkl]

In progress, weight situation

I bought a partly completed Wag Aero Sport Trainer fuselage and made the necessary modifications to have an almost 100% PA-11. I completed the rest and I am ready to cover.

You are right. I tried to keep it light so far and there is no turning back. I was just wandering if someone had weighted their fuselage before cover for comparison.

Thank you for your comments.

GDKL

 

[Steve's Aircraft (Brian)]

We did not weigh our Super Cub fuselage before or after all the modifications. We did however weigh the airplane for a before and after the cover. She weighed 1110 before, and now weighs 1080 after. Stewart system on the fuselage. Hope to lose some more weight when we recover the wings.

Just look for everything that adds weight that you can live without. We changed to lightweight starter, oil cooler and battery. Got rid of all the insulation in the cabin. Added X brace and seat belt attachments. Made all new interior panels out of .016 instead of the .025 that was in it before. Like Courierguy said, be anal about it and you will have a great performer.

Brian.

 

[behindpropellers]

We did however weigh the airplane for a before and after the cover. She weighed 1110 before, and now weighs 1080 after. Stewart system on the fuselage. Hope to lose some more weight when we recover the wings.



Brian.

Very impressive. Please post where to buy the helium filled covering system :lol:

 

[gdkl]

Thanks Brian for your comments. I did buy a light weight starter and B-C alternator plus an Odessey battery. The inside paneling is .016 as well so I should have a decent empty weight. I have a set of EDO 1400 to put on.

I hope to operate the aircraft at around 1400 lbs for good performance.

 

[behindpropellers]

Did you put the PA-18 topdeck in it?

Tim

 

[gdkl]

My project has the J-3/PA-11 topdeck.

 

[Leniuk]

Just curious, what changes did you make to the fuselage to make it 100% PA-11? I am currently working on the same sort of project. My difference will be no electrics and flaps.

 

[gdkl]

Here is a list of modifications I made from the Sport Trainer Wag Aero plans into a PA-11 look alike:

Different engine mount tilted down by 2 inches. (PA-11 engine mount different from J-3)

Cowl boot and firewall PA-11 style.

Stringers to round -off the fuselage.

Different struts. (check with Wag Aero). No flaps.

PA-11 nose piece and cowling.

Cowling bumps on top cowling to clear spark plugs.

There might be other changes that I made but I cannot recall at this time, but basically this is it.

gdkl

 

[aktango58]

You might regret the engine mount tilted down

quit eating, will cut weight fast :lol:

 

[behindpropellers]

I would do some reading on here before you make any more changes.

If I were were to build a PA-11 clone it would have the J-3 mount and the PA-18 topdeck so the spars are away from your head.

Tim

 

[cubdriver2]

Tim I agree with you on the top deck, and I know all you SC guy's like the thrustline mod, but I think that the stock pa11 mount is fine for the weight that it fly's at, never lost a TO to a SC when we were both solo, but then again I never got to go up against one with a TL mod.

Glenn

 

[behindpropellers]

never lost a TO to a SC when we were both solo, but then again I never got to go up against one with a TL mod.

Glenn

Glenn-

My J-5 has never lost to a takeoff contest with a supercub, either

 

[willyb]

Glenn I would highly recommend a 0 thrustline if you can do it.My 0-200 cub definitely likes it and not just take-off performance it is faster and handles better all around.

Bill

 

[cubdriver2]

Bill, I've got over 2000 hr in it the way it is, I don't know if I could handle it being better. :-?

Glenn

 

[ag-pilot]

pa 11

Glenn,

You would soon change your mind after flying a 0 TL -11 Never flew one but the way it helps the 18s it has to do alot for the 11. Maybe not as much on takeoff because you have less downward thrust loading the wings with the lower HP but on landing, turning and climbing I bet its way lighter feeling.

Are the lakes hard yet?

dave

 

[Tim]

Glenn, you have alot more to worry about than the thrustline on your 11

Tim