40"(or so) SeaHawk - Help

[flyingscot]

HI guys, I am looking to put together a Hawker SeaHawk of around 40" span.

Normally I would throw a plan together in AutoCad but this one has me turning over in my sleep.

Cant decide on the best way to do the blended fuselage/wing arrangement. Most of my previous models have just used fillets etc. L59, Sabre, Hawk etc.

This one has got me wondering about a bottom mounted wing or plug in panels or a blended one-piece.

I know Chris Golds has a plan for a 60" DF but alas cant find a 40"-ish let alone one I can use as a template.

Any help, assistance or push in the right direction would be greatly appreciated.

[gazza]

Hello Flyingscot.

At last another Seahawk fan.!
I too have been driven nuts trying to draw this one up, and figure out how to put it together.
ultimately I would like the design to be for a kit for 70mm EDF but efflux and intake areas are a headache if scale is to be adhered to (Essential obviously.!)
I was hoping to build a PSS version first, true to scale, to help me get my head round making a fan version.
I have got as far as CADing up some sections and my pal Mike at Green Air Designs has made some 3D renderings from these. They still need some work, but we are close.
Mike is using a technique now, using 3D cad drawings to drive a 3D router. By routing two halves of, say, a fuslage, it is possible to have an acurately machined outer shape and insides too.
Materials used are rigid foams.
In the case of the Seahawk we were thinking of employing a horizontal split on the fuz, with the fuz including the wing roots, fillets, intakes and exhuasts (Up to the wing hinge line in fact).
The wing panels would then be CNC hot wire cut to an aerofoil of our choice depending on whether it was for PSS or EDF.
This method produces a kit very quickly with a LOW parts count, not dissimillar to a foam ARTF, but with lots of advantages to us "proper" builders regarding versatility especialy at the design stage.
A Seahawk for instance could be built as a "one piece" as you suggest (My choice too) or with detachable wings, or even scale hinging wings..(Why??)
The Seahawk is a tricky one as you say, and if I'm honest I could do with a like minded soul to help me persuade Mike to improve his 3D renderings to a cutable stage. If you are interested in swapping notes and encouragement, there would probably be a cost price proto-type in it for you at the very least.
If you can draw with SolidWorks in 3D then you are looking at virtually any model you can draw, by return of post (nearly..!!)

Have a look at the GAD site for more info on"Generation V" methods www.greenairdesigns.com/gadejcforum/index.php

I hope you can see the potential for PSS models with Gen V, I am trying to persaude Mike to offer PSS versions of his kits, which have always been exclusivly electric. So any help will be greatly recieved.

Cheers

Gazza

[gazza]

Sorry the link I gave above is a bit too broad...Hope these two narrow it down a bit.
greenairdesigns.com/gadejcforum/index.php?topic=257.0
greenairdesigns.com/gadejcforum/index.php?topic=237.0

Also forgot to mention that the Seahawk that I was planning would work out at about 1200 to 1300 (48" ish) span for a 70mm fan. But one of the big advantages of CNC production and CAD drawings is that the model can be cut at any size desired within material limitations at the mere click of a mouse. So once the thing is drawn up, a 40" Seahawk is no problem.

Cheers

Gazza

[flyingscot]

Very impressive 3d renditions, do me a favour and give Mike a slap on the back for me. Not just for the 3d work up but also for the FW190 kit he put together for me a few years back.

Very encouraged by the thought of a clam shell style kit, at 48" to 50" it would be more capable of taking a glass skinning for PSS work. Chances are you could do a brown paper job for the d/f guys or maybe even just a paint job.

Tell me what I can do to help and lets get the ball rolling and the router spinning. ;D

[flyingscot]

My initial thoughts would be for an Eppler 374 at both the root and tip with around 5 degree tip washout.

Maybe a set of inboard flaps for a little positive reflex on the howler days and a little normal flap for lift on the calm days.
I don't think I would bother with crow's, would be a bit OTT for something like this and probably totally un-necessary.

I have recently been exchanging emails with Terry Lidstone on the subject of Seahawks, Terry recommended an Eppler 374 for the root and a SD3021 for the tip, I would still be inclined to add a little washout.

Hope this helps or maybe even encourage others into a bit of debate or brainstorming.

[gazza]

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Ha ha! yeah he would appreciate a slap on the back...I usually creep up behind him and give him a big kidney bosh..Tee hee!

Glass skinning is no problem. We regularly use 18gm per sqM glass cloth all over even little models (28"). Applied with water based Polyurethane Varnish, doubled up or more on say, the LEs and belly.
It's a very good substrate for paint, gives a lot of scuff protection and a bit of strength. But not so much as to stop a clean snap if the model cartwheels in. The weight of a pusher motor for instance will soon have the empenage off, but the clean break is easy to mend.

PSS models will tolerate a lot more skinning, and don't have the overhung masses of motors and flight packs either, so longevity will be much better.
I have no experience of brown papering, but I have no doubts that it works....not sure about the weight compared to glass cloth and epoxy though? ...Depends how much you lard on I guess..!!

Always prepared to take advise on aerofoils, and at the end of the day the choice is yours. These days GAD models tend to have a modified sort of Clark-Y which Mike has evolved, and it works very well indeed on electric models.
about 4 or 5 degrees of washout is pretty standard too...all easy stuff with a CNC hot wire cutter.. ;D (Blessed aint we??)

I intoduced Mike to some very cheap and lightweight alloy box section some years ago, and this is now standard fitment to all foam wings. In fact Mike is now using ever bigger sections of this as his models get bigger..It's proper strong.!

The format for a PSS version of "Gen V" model is evolving in my tortured mind, and might have some thick internal bulkheads where the EDF and ducts would normally be. It could also feature a strong tray about the CoG for ballast, and obviously some neat compartments for the Rx and it's battery.

I like your ideas for various flappage on a Seahawk, you sound like a very spirited flyer....Bring it on..! ;D

My preference would be for some scale working U/C and a working arrester hook....Not for landing on of course..Just for posing with the odd dirty pass.

You need to get in touch with Mike and have a natter about the Seahawk, see if you can get his juices going, and you never know what might happen.
I will try to PM you with his contact details, or have a word with the nice admin folk and see if I can post them here.
In fact come to think of it you can get the details from the GAD website.

love your enthusiasm Flyingscot, lets roll with this one..!! next on the list are the Scimitar and Buccanneer.. ;D

Cheers

Gazza