[f-AA] Weight of Al spars--was "New spars--questions"

[Jerry Jackson]

Here is a comparison of weights between wood versus Aluminum spars (by
Milman) .

Weight of just spars for two wings: Wood--42 lbs Al--46 lbs

Weight of spar fittings for two wings: Wood-- 0 lbs Al--12 lbs

Total weight of spars plus fittings: Wood--42 lbs Al--58 lbs

Weigh of leading edges for two wings: Old-- 10 lbs New
(thicker)--14 lbs

Total increase in weight:
Total--+20 lbs

I am happy to accept that penalty to escape the necessity of annual spar
inspections. And choosing a light-weight covering system can save that much
or more.

Jerry Jackson
7ECA
8T8

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[Richard Holcombe]

If under 100 HP spar inspections are only one time, not every year.

If I got the new spars and recovered I would undoubtedly add a wing tank, and all other weight considerations would be out the window.

 

However, what "light weight" covering system?

 

 How do the systems compare? Someone must have used various systems and have informed oppinions about them. My only experience is with Stits and I really liked the easy repairability of the low gloss paint.

My current bird has Air Tech. I got the book, but haven't read it yet, on the system, and have not yet tackled the touch ups it needs.

[Rainbow Flying Service]

Jerry and all; I would like to weigh in on the wood vs. metal spar debate.
As many of you know I make new wood spars for Aeronca's and Citabrias. Wood
spars are the cheapest and lightest. Many of the wood spars in these
airplanes are 50 to 60 years old and have given good service. My new wood
spars are sealed with 3 coats of epoxy varnish. This is much better than the
old varnish. Even so the spars in the wing are protected by the wing
covering. The biggest weather problem is the butt end which is exposed in
the gap between the fuselage and the wing. I put about 10 coats on the butt
end for this reason. Keeping an airplane in a hangar helps with this
problem also. My wing inspection kit makes the spar inspection easy to do.
My kit is to install two holes on the top of each wing. Thy are flush,
sealable and secure. rainbowron

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[Kyle Boatright]

As someone else brought up, if anyone has real world data on covering system
weight, I'd love to hear it. I've talked to the tech support folks with two
of the major systems and both claim to be the lightest by a fair margin. I
may not be the smartest guy around but I don't believe that two different
sytems can each have a legitimate claim to be lighter than ALL the other
systems.

Also, while I'm on a weight binge, what are the lightest Chiefs and Champs
out there? If your bird is on the lighter side, speak up. What's it weigh?
What equipment do you have installed? Metal or wood prop? Which covering
system?

I've got reference books that claim as low as 725 lbs, but I have never seen
a post-war Aeronca that claimed to be anywhere near that weight. And with
the modern, lighter, covering systems, you'd think some aircraft, at least
the ones with no electrical and a wood prop would be under this seemingly
mythical figure of 725 lbs.

[Mike Knemeyer]

Both of my champs were 755# one actual other stated calulated, from the factory A65 wood prop. Now one is 780# the other is under restoration.

 

Mike K

--
Mike & Melva Knemeyer

[Ian Harvie]

I thought the cut-off was 90 HP for the inspections.

Ian

[j...@joea.com]

Ian,

You are correct.

Joe A

On 18 Nov 2008 at 19:25, Ian Harvie wrote:

> I thought the cut-off was 90 HP for the inspections.
>
> Ian
>
> Richard Holcombe wrote:
> > If under 100 HP spar inspections are only one time, not every year.
> > If I got the new spars and recovered I would undoubtedly add a wing
> > tank, and all other weight considerations would be out the window.
> >
> > However, what "light weight" covering system?
> >
> > How do the systems compare? Someone must have used various systems and
> > have informed oppinions about them. My only experience is with Stits and
> > I really liked the easy repairability of the low gloss paint.
> > My current bird has Air Tech. I got the book, but haven't read it yet,
> > on the system, and have not yet tackled the touch ups it needs.

[Rob McDonald]

Hi Kyle,

Here's another data point:

1946 7AC
Non-Electric
A-65 / Wooden prop
One 5.5 US Gallon wing tank
777lb - This is calculated from a weighing done after the 1963/64 rebuilt when it was imported to Canada.

Rob McDonald
Owen Sound, Ontario

[Richard Holcombe]

90 HP is Under 100 HP. we are both correct on that point.

I would still like to hear discussion of various covering systems reguarding weight, UV resistance, and reparability of the paint system.

I have the Air Tech system. It uses epoxy paints with a UV filter, but no silver undercoat. It was applied in 2001 and seems to be doing fine, although there are a couple of hanger rash spots that could be redone. I just wondered if anyone out there has worked with the system and has any free advice.

richard

[j...@joea.com]

Sorry, but the correct statement is "under 90 hp" the inspections are a one
time affair, not every year. Not "under 100 hp" as stated before.

The FAA does not work this way and everyone does not always win nor get
an "A."

Ian's statement is correct.

Joe A

On 18 Nov 2008 at 7:41, Richard Holcombe wrote:

>
> 90 HP is Under 100 HP. we are both correct on that point.

> richard
>
> On Tue, Nov 18, 2008 at 4:35 AM, <j...@joea.com> wrote:
> Ian,
>
> You are correct.
>
> Joe A
>
> On 18 Nov 2008 at 19:25, Ian Harvie wrote:
>
> > I thought the cut-off was 90 HP for the inspections.
> >
> > Ian
> >
> > Richard Holcombe wrote:
> > > If under 100 HP spar inspections are only one time, not every year.

[Cy Galley]

The wording is (2) Group 2 airplanes: ACAC Models 7ECA, 7GC, 7GCA, 7GCAA, 7GCB, 7GCBA, 7GCBC, 7HC, 7KC, 7KCAB, 8GCBC, and 8KCAB airplanes; and any of the airplane models referenced in paragraph (a)(1) of this AD that have been modified to incorporate an engine with greater than 90 horsepower.

 

If you have a 90 HP or an 85 with the O-200 crank, the inspection is a one time complianace. All others is is yearly which is should be on a ALL good annuals despite the AD and the horsepower.

 

Cy Galley
Editor - Aeronca Aviator
Supporting Aeroncas everyday
www.aeronca.org

 

[Cy Galley]

AD says... GREATER than 90 hp ; (2) Group 2 airplanes: ACAC Models 7ECA,

7GC, 7GCA, 7GCAA, 7GCB, 7GCBA, 7GCBC, 7HC, 7KC, 7KCAB, 8GCBC, and 8KCAB
airplanes; and any of the airplane models referenced in paragraph (a)(1) of
this AD that have been modified to incorporate an engine with greater than
90 horsepower.

Cy Galley

Editor - Aeronca Aviator
Supporting Aeroncas everyday
www.aeronca.org
----- Original Message -----
From: <j...@joea.com>
To: <aer...@westmont.edu>
Sent: Tuesday, November 18, 2008 9:47 AM
Subject: Re: [f-AA] Weight of Al spars--was "New spars--questions"

[Richard Holcombe]

My 7ccm got reweighed last summer and gained a bunch of weight over the old published figures. It was my IA's way of making me actually seriously do a loading chart and weight and balance. The only problem came up when I had to ask my wife what her actual wieght was. We did get over it with time. we are at gross but within the CG.

 

7CCM, Air Tech coatings system, wood spars, no electrical system, one 5 gallon wing tank, C-90, Scott tailwheel, and Cleavland wheels and brakes. Maps and handhelds.  810 lbs.

[Jerry Eichenberger]

I don't understand why people weigh airplanes without a compelling reason.  They will always be heavier, after time has passed, than the calculated weight.

 

In our FBO, years ago we bought a Beech Skipper for a trainer.  The idiot IA who worked for us back then promptly weighed it, did a new W&B, all before the owners knew what he was doing.

 

It ended up that they airplane was useless as a trainer, since it was now legally a single place airplane, and couldn't be used for checkrides, since with a pilot examiner on board, everything needs to be on the up and up.  That is if you wanted enough gas in it to be able to do more than 3 touch and goes.

 

Be careful when some IA wants to weigh your airplane during an annual, just out of his curiosity.  You may not want to know the answer.

 

Jerry E.

[Thomas DeWinter]

With all due respect.  You may not want to know the answer as to how much it weighs.  But there is safety, legality and liability to also be concerned about.

 

Fo example:  What about if there was a crash the insureance Company won't pay since you were over gross or out of W&B?  Or what about the family of the student suing the flight school and/or the instructor for "letting" them fly an airplane that is over gross or out of W&B?  Is the argument that the CFI had no way to know because the owner of the plane did not have a current W&B done on the plane really mean squat to a jury who is sitting there watching the widow cry?

---

From: Jerry Eichenberger <jeiche...@ehlawyers.com>
To: aer...@westmont.edu; r...@sunrisetechnical.ca
Sent: Tuesday, November 18, 2008 11:05:01 AM

[Thomas DeWinter]

With all due respect.  You may not want to know the answer as to how much it weighs.  But there is safety, legality and liability to also be concerned about.

 

Fo example:  What about if there was a crash the insureance Company won't pay since you were over gross or out of W&B?  Or what about the family of the student suing the flight school and/or the instructor for "letting" them fly an airplane that is over gross or out of W&B?  Is the argument that the CFI had no way to know because the owner of the plane did not have a current W&B done on the plane really mean squat to a jury who is sitting there watching the widow cry?

---

From: Jerry Eichenberger <jeiche...@ehlawyers.com>
To: aer...@westmont.edu; r...@sunrisetechnical.ca

Sent: Tuesday, November 18, 2008 11:05:01 AM

[Tom Holmes]

I recently bought a project Champ and have been poking around in it while flying.  So far I've pulled at least fifty pounds of mud dauber nests out of the wings and from under the floorboards, and behind the instrument panel, and several live 12 gauge rounds. Tom, preparing for winter. --- On Tue, 11/18/08, Jerry Eichenberger <jeiche...@ehlawyers.com> wrote:

[Rob McDonald]

On Tue, 2008-11-18 at 11:51 -0800, Tom Holmes wrote:

I recently bought a project Champ and have been poking around in it while flying.  So far I've pulled ..... several live 12 gauge rounds. Tom, preparing for winter.

Sounds like the previous owner was ready for a ramp check :-) (Sorry Gregg)

Rob

[Spence, Mike]

Sorry Jerry - I wouldn't call the IA an idiot at all - That's just s m a r t !

________________________________

[piper...@charter.net]

My 11AC weighs 745 pounds. I used the Superflite system and I have a metal prop. wheel pants, and a McDowell starter. That makes for a 505# useful load. I will be glad to bet anyone a case of beer that you will find it at that weight.

Jay