Lambro

I am building retracts into a set of .40 Great Planes Kit Balsa floats. It has been quite an exploratory ordeal, complicated by the fact that I am not a greatly experienced builder. Has anyone else attempted this?

Lambro

Well, piddle, I would like to post some photos of these amphibious GP.40 floats, but for the life of me cannot seem to figure out how to do it? Could someone help this clueless one?

bikerbc

I am no good at posting photos, I always need to get my wife to do it for me...But I sure would like to see what you are doing...I usually make my floats from solid foam and cover them with glass...That way you never get leaks...What type of retracts are you using ? Mechanical ? It would be nice if you could use electrict but I don't think there are any waterproof ones

scale only 4 me

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Click the button
Then scroll down and click on the "Click here to upload images and files!" link
Click the "Browse" button
Find the image where it is saved on your computer or portable disk drive and double click on it
Then hit the "OK" button,, when you see the "OK" screen you're done
Finsh posting the reply

good luck

Lambro

Hi Ken,
We will get the photo thing figured out, but as to your question, I am using the inexpensive Hobbico mechanical retracts, nose gear model, for both nose and mains. And you are right, electrics would have been wonderful, but these retracts will actually be in the water, with the wells somewhat full, when afloat.
I have the first float ready to cover and have learned a lot. I am confident they will be just fine on land, but will be fascinated to see how it goes on the water. I will likely hang them under my J-3 Cub already on floats to see.

Lambro

Thank you scale, I had been doing that previously, and it always asked for URLs, so I don't know what changed but it seems to work!

Lambro

My previous Great Planes Kit Balsas have never leaked at all. In this case now, we are chopping the bottom full of holes. Trying to waterproof the wheel wells is maddening. On this go round it entails lots of marine sealant, boots and grommets at pushrod penetrations etc. All inside wood surfaces are also coated in epoxy/alcohol and polyurethane, to keep them from rotting I hope.

I have many more photos of progress, and in fact am putting together a build file. I think some of the experience here will come up with some great improvements. Let us see if these photos work.

scale only 4 me

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If you use the (image) button link you need to use URLs,,, that's for images that are already hosted somewhere on the web.

glad to help

scale only 4 me

My Feedback: (158)

Two things I'd do differently

1- use air retracts, much easier to waterproof
2- with the gear going so far back from the step, I'd have gear doors also,, that is going to catch a lot of water

If you do insists on running the mechanical gear, I'd run a separate receiver/power system

good luck

Lambro

Actually considered each item you mentioned. Air retracts have small well mechanisms which would be good, but are otherwise a pita. The aft, main, wells are indeed far back and beyond the "dead" area aft of step. Though we obviously haven't got to water trials yet, the installation of the aft well deflector is intended to provide a bit of "lift" at pre-step speed. I am somewhat puzzled about the recommendation for seperate, or additional receiver and power. Was this because of the likelihood of things getting wet? If so, the likelihood of getting wet is actually greater in the airplane than in the floats.

Overall, the project was a sort of a whim arising because the flight simulator had a J-3 Cub on ampibious floats, yet we could find no place to purchase .40 size amphibious floats. We also wanted to invest as little cash as possible, hence the Hobbico Mechanical retracts, which are ubiquitous anyway. The mechanicals are also relatively large, so we figured if we could manage to get them into the very tight confines of the Great Planes Balsa .40 Floats, builders with more experience and a better bankroll could really do some nice installations on these very popular floats.

We appreciate the observations and recommendations...keep them coming!

scale only 4 me

My Feedback: (158)

Well, my thinking is,
With an air system you can have all the electronics, valve and servo in the plane,, just run the air lines down to the floats, just like you'll have to with those servo extensions. No electronics under the water line so if there is minor leaking (which there is sure to be) you don't fry the plane's flight system.

Same Idea with a separate flight pack,, it isolates the airplanes flight pack from the servo(s) in the float. I've seen a few guys do this in larger planes with retractable water rudders and to run the water rudder steering also.

good luck

bikerbc

I had to look up ubiquitous because it is a 50 cent word and I had no idea what it ment..

Lambro

At 50 cents, its the only place we have a high budget!

Lambro

I have a little more progress on the retract-into-float project, with a couple more photos. "Scale's" observation suggesting gear doors at the aft mains hit home, and will be installing doors when the hinges arrive. Again, I am staying with the inexpensive Hobbico mechanical retracts.