F2A- 2 Brewster Buffalo a @ 1/5 scale - RC Groups
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Oct 20, 2017, 02:56 PM
EB-66C Team Member
J Morgan's Avatar
Build Log

F2A- 2 Brewster Buffalo a @ 1/5 scale


Here's the new build of the big Buffalo. From Bates 1/5 scale gasser plans. AUW of the gasser is expected at around 28 lbs.
I plan to try to build it from foam/ply at around 12-14 lbs max( I hope!). WS is 84", L is 62" and has 1205 sq in WA. The plan is for a 3 piece wing with
retracts installed in the middle section. Yep retracts. If you're familiar with the Buffalo then you know it's pretty funky gear. Jerry drew up some
plans for the units and I did a simple mockup, they do work but would need a jackscrew or large air cylinder to operate.
I have the crazy idea that I might be able to use the Taft Hobbies main retracts. They operate off a jackscrew and are pretty robust. Trying to set them up where they can just lift the wheels up until the wheels seat and their limit switches shut them off. Figured I needed to see if I could figure the gear out
before starting the build, otherwise she will have to have fixed gear. I'm not totally against fixed gear but sure would be cool if they would retract.
You can see Jerry's design in the mockup. the top strut moves about 2.75" up to retract the gear. It looks to be a solid design but would require a machine shop, air cyl or jackscrew to operate them. I'm trying to cut out the middle man and do it all myself a simpler way......... if it will work.
This won't be a really quick build as I'm not in a hurry, want to be done for SEFF and also have some other things going on that takes up my time.
But should make progress most everyday.... unless I fail.
If you want to learn how to build lite, don't watch me, watch ALEZE over in Electric Warbirds. He has a sweet I-16 in the mix right now and shows just how
he does it. Amazing how light it is and BIG! Here's a link to it.

https://www.rcgroups.com/forums/show...f-foam-plastic

I'll show my idea of the LG here in a bit.

J
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Oct 20, 2017, 03:05 PM
I don't do Normal
Pinky_d_brain's Avatar
Me so happy. I'm looking forward to the build J
Oct 20, 2017, 03:49 PM
I don't do Normal
Pinky_d_brain's Avatar
some pics of gear

just thinking out side the box but...... put normal 90* landing gear in the large part of gear with a hinge at the end of the rod used to put the weal on. I don't have much reference on scale here so this is just an idea.
Last edited by Pinky_d_brain; Oct 20, 2017 at 04:01 PM.
Oct 20, 2017, 04:01 PM
EB-66C Team Member
J Morgan's Avatar
All I can say is I hope I don't disappoint you Pinky.

Here's what I've been kicking around on the gear. Using the Taft Hobby main electric retract unit.
It's all alum and pretty stout jackscrew driven with a control box that has limit switches both ways. That way I can stop it where I need w/o fear of burning it out.
This is rough but should give you the idea. I will place the unit in the wing with a stop to get the right angle in the down position. Then when the gear raises it will lift the wheel into the well and pressure up until the limit switch stops it. Using Dubro or Dave Brown lite weight wheels.
Using a Robart series # 650 strut, cut off the top for correct length. Then a 5mm piano wire is a very snug fit( I actually have to emery cloth it down a bit) in the retract and the lower end affixed to the Robart strut.
I think the unit is strong enough to handle a 12-14 lb airplane. Only thing I worry about is maybe side loads on a less than perfect landing.
Anyway, now I am sanding the 5mm wire down a bit to get the absolute correct fit in the unit.

The fuse on Jerry's plan is built top half first and then the lower added. Heck, I never can build to plans like it was intended. So I will be building it as a half shell, Guillows style. Using my light box to trace the formers which will be 1/2" blue foam. I'll be covering it with 3 mm MPF which is nice because Jerry has 3/32" balsa as sheeting. That means I don't have to redraw the formers since I know I will be sanding off at least 1/32" when finishing.

J
Oct 20, 2017, 04:05 PM
EB-66C Team Member
J Morgan's Avatar
Quote:
Originally Posted by Pinky_d_brain
some pics of gear

just thinking out side the box but...... put normal 90* landing gear in the large part of gear with a hinge at the end of the rod used to put the weal on. I don't have much reference on scale here so this is just an idea.
Pinky,
As I see that drawing, it's basically like the real thing and Jerry's in that you need the motion inside the fuse to activate the procedure of up and down.
The hinge point is up in the wing and the gear just swivels there. I'm trying to get away from anything in the fuse and do it all with the unit in the wing.
Talked to Wade about it ( of course) and he was concerned abut the strength in the wing. But I think I can harden that area pretty easy and spread the load out through that section.

J
Oct 20, 2017, 04:41 PM
Registered User
That looks like a good plan.

Now if you could implement a functional "retract link" in the drawing above to brace the gear leg that would take a lot of force off the retract unit and mount.
Oct 20, 2017, 04:45 PM
Foam abuser!
crxmanpat's Avatar
Signing on to watch another awesome J Morgan build come together!

Pat
Oct 20, 2017, 04:57 PM
EB-66C Team Member
J Morgan's Avatar
Quote:
Originally Posted by pmullen503
That looks like a good plan.

Now if you could implement a functional "retract link" in the drawing above to brace the gear leg that would take a lot of force off the retract unit and mount.
Yes Pat, it will need that inner folding strut. Haven't gotten far enough into it to come up with a plan for it yet. If I can make it functional that would temper my
side load worries.

Guess I will be bending piano wire tomorrow, another job that isn't much fun since both need to be really close to the same.

AZ Pat
We can only hope so. If I can get past these retracts it will be a breeze after that.

J
Oct 20, 2017, 06:12 PM
Veni Vidi Volavi
Brian Allen's Avatar
J

Will be watching with much interest. The plan sheet for the landing gear in Post #4. Is that from the 1/5th scale set of plans or the 1/2 scale set? As I noted to you previously my 1/5th scale set does not contain that sheet.

Brian

Veni Vidi Volavi

I came I saw I flew
Oct 20, 2017, 06:49 PM
EDF rules... :)
AirX's Avatar
Quote:
Originally Posted by crxmanpat
Signing on to watch another awesome J Morgan build come together!

Pat
Yup, Iím in for the ride.

Cheers,
Eric B.
Oct 20, 2017, 07:09 PM
Registered User
Doug Bartley's Avatar
I'll also be watching this one John!! Give yourself time to think thru the LG, it will come to you with a night or two o sleep (you hope) hehe Doug B
Oct 20, 2017, 07:10 PM
Registered User
Meatball's Avatar
Subscribed!

R
Oct 20, 2017, 07:32 PM
I may be some time ....
balticS2's Avatar
Looking forward to seeing you breathe life into this one.

I thought a screw jack might be a solution for the Buffalo u/c when I saw Sopwith Mike using one on a tip float a while back

All the best

Alec
Oct 20, 2017, 07:41 PM
Oh no, not again!
jhspring's Avatar
Yah, what they said. Always a pleasure to watch you work, John and I learn with every build. Thank you for taking the time and trouble to document it for us hangers-on.

Regards,
Jeff
Oct 20, 2017, 08:17 PM
Registered User
Me ++++++ whatever will be watching you, John.

Den


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