By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by CML

U-2 Dragon Lady

"A dance with a lady or a fight with a dragon" 117" span Jack Lynn Bale plan

All Topics | Latest Posts

Search for:  in Thread Title in  

Chris Barlow11/12/2016 05:32:27
avatar
1781 forum posts
1208 photos

The quickie A-10 build is now pretty much at the paint stage so there's some down time between coats to make a start on a more scale subject. I've quite fancied a U-2 after seeing Harry Twists foamie U-2 flying throughout last year looking very graceful in the air. Looking on Outerzone I found a nice looking plan by Jack Lynn Bale here.

plan image.jpg

It's 117" span (3m less an inch) for EDF or slope and big enough for some detail work and a cockpit for which I'll blatently copy Phil Cooke's techniques used in his big A-10 blog.

Tonight I've printed off the plan and stuck the pages to make the 2 sheet plans. I've also printed individual sheets off for the formers and wing ribs ready to turn into templates. Before I make a big start I'd appreciate any input and suggestions on the plan, for example, since there will be no landing gear I don't think I need to cut some formers from 1/4 ply. I'm also thinking of using a wing tube instead of the designed ply spar arrangement.

This isn't going to be a quick build but I hope to have it ready before summer 2017.

Piers Bowlan11/12/2016 07:41:34
avatar
1632 forum posts
41 photos

Any thoughts on the wing section Chris? Will you be sticking to the one on the plan or perhaps using a semi-symmetrical section of some sort? Following with interest.

pete taylor11/12/2016 10:07:02
avatar
348 forum posts
162 photos
Spookily enough, I've been pondering this plan, but for a 90mm edf unit.
Carbon tube wing and tail joiners are almost a given these days, but the wing section has a few possibilities.
The section that I'm planning to use is MH32 fo and it's all round performance.
Any observations will be gratefully received.
Chris Barlow11/12/2016 11:07:45
avatar
1781 forum posts
1208 photos

Piers, I was thinking of sticking to the wing section on the plan as I wouldn't even pretend to know more than the designer and also it's pretty similar to the wing section of most of my other PSS stuff. I won't be asking it to go at insane speeds or pull any high "g" or snappy moves so I think it may be OK for scale flight.

Pete, whilst snooping around the internet I've seen a few different forum posts from people planning to use a 90mm 12 blade fan, but not found any examples of them being built. When you stick the plan together you realise it's quite hefty for EDF and would need a powerful and efficient unit.

john stones 111/12/2016 11:13:33
avatar
10141 forum posts
1475 photos

Great subject Chris, you be posting the build ?

John

Chris Barlow11/12/2016 12:13:54
avatar
1781 forum posts
1208 photos

Yep, build photos included when I get started John. yes

Piers Bowlan11/12/2016 13:51:25
avatar
1632 forum posts
41 photos

MH32 sounds good Pete and similar to Eppler 205 for good penetration. Should fly well regardless Chris with it's high aspect ratio and small frontal area. Should be a superb looking model too, judging by your other builds.

MaxG11/12/2016 16:32:57
143 forum posts
3 photos

Cyril Carr does a plan for a U2. It is to fit a 90mm edf. It also has some alternatives on the plan for a PSS version. All about intake size but at present I cannot remember which is the more scale. They all look good to me.!

Used to watch them at RAF Alconbury. Near Inwood models. Could see them whilst driving on the A1. The take off angle was akin to an overpowered Wot 4!!

As an aside, Alconbury used to have a nice Aggressor F5 as the gate guardian.

Maxg

lightning 75911/12/2016 17:37:24
avatar
148 forum posts
10 photos
Posted by MaxG on 11/12/2016 16:32:57:

As an aside, Alconbury used to have a nice Aggressor F5 as the gate guardian.

Maxg

was a fiberglass one I believe

andy

Martian11/12/2016 18:07:53
2059 forum posts
1010 photos

what a belter its a lovely looking plane it can,t fail to have presence

Harry Twist11/12/2016 20:02:22
276 forum posts
196 photos

Hi Chris, Great choice and nice looking model - I thought my U2 was big enough at 2m but yours at 3m will have lots more presence. As others have mentioned - I would spend some time considering the best wing section to use - mine floats reasonably well (mainly because it is so light) - but the wing section is nothing special and in marginal conditions it becomes a scratch session when compared with gliders of similar span and wing area. Also - minor issue really - an all black aircraft ( if you do yours all black that is) can sometimes lead to orientation issues (well, for me it does!) - so you have to keep your eyes on it!

Looking forwards to following your build.

Edited By Harry Twist on 11/12/2016 20:06:16

Andy Meade12/12/2016 09:49:52
avatar
2488 forum posts
639 photos

Should be good, Chris. Are you going to fit a fan as well, "just in case"?

As for the wing, personally I'd be looking at something of high efficiency - maybe an RG14 or 15, and get it CNC cut with spars and vac bagged by Cloud Models yes

Martyn K12/12/2016 14:13:19
avatar
4783 forum posts
3464 photos

I'll be watching this one as well Chris.

Wikipedia has a lovely description on how difficult it was to fly - only 10kts between stall and max surprise

 

The original had a wingspan of 30m - so I guess this will be 1/10 scale.. That will make detailing a challenge for you

 

Good luck..

 

Martyn

 

Edited By Martyn K on 12/12/2016 14:13:35

Chris Barlow12/12/2016 19:34:11
avatar
1781 forum posts
1208 photos

Interesting ideas on the wing section. Would a more efficient section increase the wind speed range, from slow to fast, and make it more versatile ? Does the plan wing section limit it to narrower speed range?

Any ball park figures on how much a cut, sparred and skinned wing may cost? That maybe a better and cheaper way to go with the wing regarding materials and time.

Chris Barlow12/12/2016 19:39:39
avatar
1781 forum posts
1208 photos
Posted by Martyn K on 12/12/2016 14:13:19:

I'll be watching this one as well Chris.

Wikipedia has a lovely description on how difficult it was to fly - only 10kts between stall and max surprise

The original had a wingspan of 30m - so I guess this will be 1/10 scale.. That will make detailing a challenge for you

Good luck..

Martyn

Edited By Martyn K on 12/12/2016 14:13:35

Yes, "coffin corridor" sounds quite frightening!

Funnily enough it must have been the TR-1 I was thinking of when you were considering choices before settling for the FD Martyn! blush

pete taylor12/12/2016 19:40:46
avatar
348 forum posts
162 photos
I haven't got a quote yet Chris, but I'm leaning towards blue foam wings with hardwood leading and trailing edges and a carbon/balsa spar arrangement. This would be finished with the brown paper and pva method.
Light, strong and fairly cheap!
Andy Meade12/12/2016 19:43:01
avatar
2488 forum posts
639 photos
Both RG sections were known as very good F3F sections back in the day. My Pike uses one, for instance. I'd expect the wings to be in the 180 to 200 quid range, with spars, bagged epoxy cloth under the obechi skins.

Edited By Andy Meade on 12/12/2016 19:44:28

Chris Barlow12/12/2016 20:09:17
avatar
1781 forum posts
1208 photos
Posted by Andy Meade on 12/12/2016 19:43:01:
Both RG sections were known as very good F3F sections back in the day. My Pike uses one, for instance. I'd expect the wings to be in the 180 to 200 quid range, with spars, bagged epoxy cloth under the obechi skins.

Edited By Andy Meade on 12/12/2016 19:44:28

I need a cloth to clean the coffee off the screen! surprise

I'm sure they're worth every penny but certainly not what I was expecting! laugh

How much is NiChrome wire? I do have a roll and might have finally have a go myself. It could all go horribly wrong but it'll be interesting!

What are the benefits to a foam skinned wing over a built up wing? I can see that for myself I would be able to repair or re build a balsa wing quite easily if I had to.

ERIC CLAPHAM12/12/2016 20:25:41
71 forum posts
5 photos

These are the wing sections of a 72" U-2 plan that I have had in the "I'll-build -that-one-day"drawer for the last 40-odd years.......as you do ! From Flying Models mag. for .10/.15 power.scan 1.jpeg

Andy Meade12/12/2016 20:31:07
avatar
2488 forum posts
639 photos
Foam wings are far easier to repair than built up stuff imho. No shattering of skins or splattered ribs to deal with. Please feel free to check with Cloud yourself, but I've got a couple of quotes off them recently and that is about what you'd be looking at I reckon.

They are quality cut on a CNC foam and vac bagged so are very tough and very accurate, which is generally not what you'll get from a built up wing, even with laser cut ribs. If you're looking for a quality wing that'd the most efficient, that's the way to go. Sometimes it's worth spending a bit for quality.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of RCM&E? Use our magazine locator link to find your nearest stockist!

Find RCM&E! 

Latest Forum Posts
Support Our Partners
Gliders Distribution
Revoc
CML
Overlander
Wings & Wheels 2018
Motion RC
electricwingman 2017
Airtek Hobbies
Slec
Sarik
Advertise With Us
Latest "For Sale" Ads
Which part of building a new traditional balsa aeroplane do you enjoy the most?
Q: Which part of building a new traditional balsa aeroplane do you enjoy the most?

 Research & choosing the model
 Building the fuselage
 Installing the engine and radio systems
 Building the flying surfaces
 Covering/painting/finishing
 All of it!
 None of it. I'd rather someone else did it!
 Other

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us