Historical Accuracy in Radio Installation, which way to go?

[L-4Pilot]

When the O-58A left the factory the aircraft did not have a rear throttle and the Learadios were mounted on a wood shelf exactly where the rear throttle would have been. Per the budget report dated 4-2-1942 my O-58A was reclassified as a L-3A and some L-3A aircraft had rear throttles added between late 1942 and 1944 forcing the relocation of the radio equipment. My aircraft was not converted and the 2nd throttle was added in 1945 as a requirement for Civilian certification.

Since my rear throttle cannot be removed (FAA certification requirement) I will have to relocate the radios to a new position in the aircraft.

There are no known period photographs of L-3A interiors, only twenty were built and there are none still flying. It is not known where the radios were moved when the 2nd throttle was added.

The Learadios are smaller than the RCA units and are 1/2 inch shorter and 1/4 inch more narrow. They slide perfectly thru the space created between the top tubing and the window frame. A complicating factor is the trim mechanism located up on the top left side but after rigging the old trim cable and aileron cables there was no conflict with the radios in this position. The trim cable moves freely above the radios with no interference, an RCA radio in this position would not work.

The 2nd option for relocating the radios is to mount one on the top left side and the 2nd unit on the floor between the pilots legs as some B models were done.This method however prohibits the rear observer from operating the radios.

I wanted to get some input from before I make the final decision on the relocation of the radios but am currently favoring the top left side location. Attached are a couple of pictures but the final installation would move the units closer together and slightly back in to the wing root.

If by chance a photo of a L-3A interior with a 2nd throttle installed were to come available I would go with the radio installation shown in actual use, it is possible that the Army may have tried both setups. Here are some photos of a test installation and a B model with RCA radios installed in the same location. The Leardios fit perfectly while the RCAs must be mouinted in front of the recess instead of back in it.

And yes the trim mechanism is installed correctly on it's side.

Thanks Guys,
Steve

[SaxMan]

If it was my plane, my question would be: If you were flying one of these in combat, which location would have been the more practical one to locate the radio? Put yourself in the mindset of a crew chief trying to figure out the best location.

The other thing I would consider is form usually follows function: If it looks right to you, it probably is right.

[Taigh Ramey]

How about the manufacturers production drawings or blue prints. Are they available on microfilm? Not sure they are open yet but try NASM archives at Dulles.

Try looking at WWII ads in period magazines for Learadio to see if you can spot the install. There's a chance it could be there as the manufacturers filled the wartime magazines with their work. Many vendors are slicing up all of the 40's magazines for their ads and you see lots of them on eBay. Several vendors at OSH also have boxes of the ads under the trade names. Maybe you will get lucky.

Is there an archives for Learadio?

Good luck

[L-4Pilot]

How about the manufacturers production drawings or blue prints. Are they available on microfilm? Not sure they are open yet but try NASM archives at Dulles.

Try looking at WWII ads in period magazines for Learadio to see if you can spot the install. There's a chance it could be there as the manufacturers filled the wartime magazines with their work. Many vendors are slicing up all of the 40's magazines for their ads and you see lots of them on eBay. Several vendors at OSH also have boxes of the ads under the trade names. Maybe you will get lucky.

Is there an archives for Learadio?

Good luck

Thanks for the comments guys. Here is the Aeronca factory drawing 7-322, my rear throttle is now mounted where the radio shelf was originally located. There are no additional drawings for field modified L-3A aircraft when crew chiefs moved the radios to allow installation of the rear throttle,. The radio vendor and factory were not involved in the relocation of the radios but Aeronca issued subsequent drawings showing later radio installations with two options as described in the opening post. I would love to find any war time pictures of either an O-58A or L-3A aircraft but they simply don't exist due to the small number (20) that were built. It would be nice if one stillexisted in a major museum but no museum has one.

[JDK]

Most of the bases have been covered, but a couple of further comments I hope are of use. As a general rule, as anyone involved in restorations (or scale modelling, publishing and other dubious arts) knows, eventually you have to go with best guess for some stuff. Then -

Good museum / heritage practice in these cases is to ensure the mod or fitment is reversible as far as possible and take minimum reasonable intervention to apply. That's good also, because -

Once you've done it, you have increased your chances of someone coming to you with the previously unfound documentation to show otherwise than your decision. (And it's not sod's law, it's a consequence of doing, not talking.)

So if you've planned to be able to adopt to new data, you're laughing...

Really hope that helps!

Regards,

[L-4Pilot]

Most of the bases have been covered, but a couple of further comments I hope are of use. As a general rule, as anyone involved in restorations (or scale modelling, publishing and other dubious arts) knows, eventually you have to go with best guess for some stuff. Then -

Good museum / heritage practice in these cases is to ensure the mod or fitment is reversible as far as possible and take minimum reasonable intervention to apply. That's good also, because -

Once you've done it, you have increased your chances of someone coming to you with the previously unfound documentation to show otherwise than your decision. (And it's not sod's law, it's a consequence of doing, not talking.)

So if you've planned to be able to adopt to new data, you're laughing...

Really hope that helps!

Regards,

Thanks James great comments. I also have the radio installation drawings for the B and C aircraft produced late that show the only other two methods for radio installation in L-3 aircraft. I think that since the Learadios fit so easily in the space above the left window it would have been relatively simple for a crew chief to have moved them straight up to that location rather than place one unit on the front floorboard and the other top left.

Here is a period photo of either a YO-58 or O-58A with the radios mounted on the window sill and they can be clearly seen thru the rear side window. This first installation was not only uncomfortable for the rear observer but difficult for the pilot to operate the radios.

Steve

[43-2195]

Steve,
This may sound a little strange, but I have found correspondence with Wright-Patterson from USAAF squadrons in combat(SWPA) which discuss engineering issues and include drawings of field modifications. They were on the unit history microfilms held at USAF Historical, Maxwell AFB. I also found the Air Depot Groups put a lot of their field modification successes on paper, in fact awards were presented to ADG personnel based on their successes(The P-47 Drop Tanks in Australia got medals for several 27th ADG men). If you know the units that operated the 20 L-3's that interest you, you might like to check out their official unit histories.
There was also a monthly magazine(A5 size) put out by Materiel service Command(sorry I cant recall the name and I'm away from my library). It deals with Tech Orders relating to USAAF aircraft of the period and has a lot of input from crew chiefs and line engineers about aircraft problems and fixes. It is full of field modifications and manufacturer responses to the problems. It may have your radio location problem covered. They come up on ebay quite often.