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Author Topic: Brodak A-1 Skyraider, Kit JR-3  (Read 2865 times)

Offline Paul Smith

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Brodak A-1 Skyraider, Kit JR-3
« on: February 13, 2007, 08:29:40 PM »
Has anybody here ever built one of these? 

I'm considering getting one and I'd like some first hand info.

It might be a good plane for Profile or Sportsman Profile Carrier.
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Paul Smith

Offline Bill Little

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #1 on: February 13, 2007, 08:41:35 PM »
Quote from: ama21835 on February 13, 2007, 08:29:40 PM
Has anybody here ever built one of these? 

I'm considering getting one and I'd like some first hand info.

It might be a good plane for Profile or Sportsman Profile Carrier.

Hi Paul,

Isn't it the old J. Roberts kit?  That was my understanding.  ???

Probably some experience with that one here, just no action on the "bait" yet. :)

Bill <><
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Offline Randy Bush

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #2 on: February 13, 2007, 09:55:04 PM »
Hi Paul,
Coincidently, I am currently reworking one of those for Nostalgia Profile.  I bought it slightly used - a 2-line setup.   It was light, fast, and maneuverable.  Now I'm converting it to Carrier, keeping it to the design so it will score Nostalgia Model points.  I'd say it's a good design.  Probably reinforcement of the wing and landing gear (wing mounted) is helpful for landing stresses.
Duane R., Alameda Aer-O-Nut, has built both the Skyraider and the Bearcat for Carrier.  One has slider; one doesn't.  One has TT 36Pro; other has OS32.  Both fly well.
Definitely reinforce for high speeds and landing forces.  Good designs but light wood, and modern RC engines can pull the weight.
All three were built from Brodak kits which are reproductions of the J. Roberts kits.
If you're in Northern California, come fly with the Aer-O-Nuts.

Randy
« Last Edit: February 13, 2007, 10:18:56 PM by Randy Bush »
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Offline Paul Smith

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #3 on: February 14, 2007, 06:55:54 AM »
I have the plans in hand.

It shows the fuselage as an open truss framework.  Is the this design intent, or did they just forget to show the sheeting?

It looks kinda light-but-flimsy to me.  I'm skert my Greenhead 35RC will tear it apart.
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Paul Smith

Offline bfrog

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #4 on: February 14, 2007, 08:50:11 AM »
I have been thinking about this same kit and I talked with a couple of people who have built both the Skyraider and the Bearcat. Yes there is sheeting over the framework but, they said the fuselage is the weak point in the design. They both said it tends to break in half on hard landings, not good for a carrier plane! From their comments I would recommend beefing up this part of the plane. I would do one of two things, make the fuselage out of half inch solid balsa or build per the plans and add an extra layer of 1/32 plywood on top of the existing sheeting on both sides of  the fuse. I guess you could glass it too but that might be heavier. At any rate do something that makes that part of the plane more robust.
They both said the plane flies well, as Randy noted. It would be a good model for starting out with carrier. Go for it and good luck.

Bob
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Bob Frogner

Offline Randy Bush

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #5 on: February 14, 2007, 09:44:38 AM »
Quote from: ama21835 on February 14, 2007, 06:55:54 AM
I have the plans in hand.

It shows the fuselage as an open truss framework.  Is the this design intent, or did they just forget to show the sheeting?

It looks kinda light-but-flimsy to me.  I'm skert my Greenhead 35RC will tear it apart.

The plan does not show or note the sheeting (poor drafting).  The angled dashed line is the joint where ply meets balsa.  All that would be clear with the kit pieces and instructions.

The fuse is completely sheeted with 1/8th":  ply for the forward 6" and the rest balsa.
The  core of the fuse is 1/2" :  Solid from nose to bellcrank mount and the rest truss framework.
The 3/4" combination is very stiff and strong overall.  I reinforced the landing hook hardpoint area by tying it into more of the framework to spread the arresting shock to more of the structure.  I used hard balsa, fiberglass, and epoxy.

Does that help?

Randy
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Offline Paul Smith

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #6 on: February 14, 2007, 12:02:27 PM »
Thanks.   That sounds better.

From the plans, the plane lacks:

Fuselage sheeting.
Wing Spars.
Center section sheeting on the wing (nothing to stick covering to).

This is for the Brodak Fun Fly.  I'm starting to question whether it's worthwhile to go for the 10-point bonus for a Brodak kit(design).   I might have to modify it so much, the 10 points will be in question.

On the other hand, I saw Skyraiders first hand at NKP and I like Skyraiders.

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Paul Smith

Offline bfrog

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #7 on: February 14, 2007, 05:08:08 PM »
I don't think its a problem if you beef things up a bit. Here's the rules for Nostalgia. The key statement is that the changes don't "significantly change the performance or appearance of the model as it was originally designed".

Go for it!!!


 5.1.     Modifications:   No modifications to the original design are permitted, except as listed below.  Any modifications other than those listed in section 5.2 which, in the opinion of the event director, significantly change the appearance or performance of the model as it was originally designed, shall not be permitted. This prohibition includes, but is not limited to, changes in airfoil, changes in dimensions, and use of moveable control surfaces not included on the original design.

 

5.2.    Allowable Modifications:

5.2.1.        Landing gear may be changed in length or material, but must exit the model at the original position.  A tail wheel may be substituted for a skid and vice versa.  Wheels may be of any diameter.

5.2.2.        Leadout position may be changed from that shown on the plan.  Ground-adjustable leadouts are permitted.

5.2.3.        Control travel, control mechanism location, and control mechanism may be changed.

5.2.4.        Tip weight may be changed or may be adjustable.

5.2.5.        Tail hook and its location may be changed.

5.2.6.        Structural changes to strengthen the aircraft are permitted.

5.2.7.        Building and finishing material substitutions are permitted.

5.2.8.        Location of access hatches may be changed.

5.2.9.        Engine mountings may be changed, and engines of different displacement may be used.gia and they allow for changing the original design as long as it keeps to the "original" performance.

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Bob Frogner

Offline Paul Smith

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #8 on: February 14, 2007, 06:00:08 PM »
The issue isn't the Nostalia Rules. 

It's the 10-point bonus for a Brodak kit at the Brodak Fun fly.  This as applied to 15 Carrier & Sportsman Profile only, not all events.   The object of the exercise is to built the plane so it doesn't fall apart amd still get the 10 points. 
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Paul Smith

Offline Balsa Butcher

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #9 on: May 28, 2007, 09:41:30 AM »
I have an original Roberts Bear kit.  It is constructed exactly like you describe the Skyraider kit, makes sense since the Brodak kits are copies of the Roberts kit.  The Roberts Kit actually specifies stiff cardboard for sheeting, a definite "no way" in my book.  My take is the built up fuselage will be plenty strong when carefully constructed and sheeted. Many have been built, although you see more Bearcats than Skyraiders.  As far as gear and a hook mount, reinforce - a lot for profile carrier, a little for profile scale.  I'm sure that would be within the rules of the Brodak fun-fly/contest.   8)
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Offline Paul Smith

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Re: Brodak A-1 Skyraider, Kit JR-3
« Reply #10 on: May 28, 2007, 09:55:20 AM »
After further review, I've decided to pass on both the Roberts/Brodak kits, (Bearcat & Skyraider) and design my own plane for regular Profile Carrier.

However, I did build a Brodak Junior Lightning Streak for 15 Profile.

Thanks for the advice on the landing gear.  As you can see, I violated it. I believe the COOLNESS of a wing gear is worth going the extra mile.  I save the wing by using really flimsy wire.  I can rebend or replace it if I ever land hard.
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Paul Smith

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