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

Neil's attempt at a first scale model!

F-86 Golden Hawk build thread

All Topics | Latest Posts

Search for:  in Thread Title in  
N Pritchett18/01/2020 13:29:19
21 forum posts

Well, here we go with my first attempt at a scale model.

Looking on the web at the wide range of livery, it had to be the RCAF Golden Hawks colours (or should it be colors) as I was from Canada many years ago.

Anyway, got the short kit, good start.

Bought the balsa etc from Balsa Cabin (they usually supply good quality).

In the process of making a building board wide enough for the wing jig (my usual board is only 300mm wide).

While waiting for the cork surface bonding to dry I started looking carefully at the Fus' drawing. With the article in RCM&E and noting the former warnings I'm hoping it will not have any surprises!

Now here's my request for help from anyone who has mastered the tail fairings please:

The Tailplane shows the joiner wire slots to be perpendicular to the fus' mating edge. OK, so next looking at the small scale plan detail, it appears to show the balsa fillet's vertical surfaces tapering towards the tail of the fus'. How does that work out?

A tricky area that I'd like to look right as I don't want to bodge this on the first attempt at scale.

Looking forward to any input, thanks.

Neil

Mark Kettle 118/01/2020 13:45:02
avatar
2519 forum posts
1541 photos

Welcome to the forum NP.

Are you building the F86 Sabre (pss glider) from the plan and kit from Gordon and Martin?

Edited By Mark Kettle 1 on 18/01/2020 13:45:27

Chris Barlow18/01/2020 14:07:08
avatar
1904 forum posts
1308 photos

Without a top view on the building plans it's difficult to see but I have tapered the tail fillets and re-cut the mating tail planes to match. It's not as much as the full size but enough to narrow it down to match the tail pipe a bit better and the mechanism still works OK.

N Pritchett18/01/2020 14:14:26
21 forum posts

Hi Mark, Yes the plans & kit from M & G.

Chris, any closeup photos?

N Pritchett18/01/2020 17:54:29
21 forum posts

been reading some of the other build threads (it's great not to be first so to be able to learn from others!)

In Steve's thread 'Avon Sabre Spirit 78' I see he is well advanced on the planking of the fus', and notice he had a case of starvation between formers 8 and 9. it's probably a result of narrow planking with light balsa which is the way I will go too. Not sure if this is common, but got me thinking.

I want to include the barn door airbrakes so methinks I'll loft an additional former '8a' half way between. Hopefully this will avoid the wasting and give the airbrakes a positive edge to close against.

I'm keeping an eye on Adrian's progress with 3d printing of his airbrakes too!

I'm already really thankful for all who are posting in the various build threads. Very helpful for us newcomers.

NP

Flyer18/01/2020 17:59:45
avatar
594 forum posts
104 photos

Good to see you building Neil,

From memory, Martin has helpfully placed one of the formers exactly where it is needed to facilitate the hinging of the air brakes.

I'm sure he will confirm in due course.

Cheers

Ade

Martin Gay18/01/2020 18:18:50
avatar
381 forum posts
254 photos

Gordon has drawn F8 just in front of where the speed brakes should be hinged. It will give you something to glue the hinge blocks too.

dirk tinck18/01/2020 18:23:36
avatar
578 forum posts
810 photos

No need for a extra former Neil .All the weight behind the CG counts double in that part of the fuse !Just add some extra stringers under,and above the brake.20191227_230020.jpg

Chris Barlow19/01/2020 03:01:37
avatar
1904 forum posts
1308 photos

Only got these 2 of the tail, and the wide angle doesn't really show the slight taper on this one. I did measure it tonight and the taper is from 49mm at the leading edge of the tail plane to 40mm over the exhaust pipe so approximately a 5mm taper on each side over the tailplane distance.

20191201_010901.jpg

20191201_010832.jpg

Gordon S19/01/2020 10:10:47
25 forum posts

Hi guys, Just in front of the fin on the fuselage plan, there is a small top view drawing which shows the fillets tapering out as they go forwards. ie narrow over the jet pipe and wider in front of the fin. In hindsight I think I should have made that clearer with either text or better drawing on the plan. (Humble apologies) From the various scale drawings we used, the angle seems to vary considerably!!!!!! As long as the piano wire pivot is free to rotate in the brass tube, it doesnt matter what angle the fillets are set to. Its the brass tube that is glued into the fuselage formers to keep everything aligned.

hope that helps??

N Pritchett19/01/2020 13:16:12
21 forum posts

Thanks Chris for the photos and detail.

Gordon, no need for apologies. You’ve done a good job in bringing the plans to the state where the Sabre can be built with only fine ‘scale’ detail to be mulled over.

I’ve been looking at photos on a ‘walkround’ Set. These appear to show the tail faces are vertical and parallel to each other, only tapering in the rear quarter of their length.

The forward part, in front of the tailplane LE merges into the fus’ as it progresses straight forward. It also has a rounded top edge in this part, but sharp edge above the tailplane and to the rear above the tailpipe.

I would include the images if I could work out how to on my iPad frown

Steve Houghton02/02/2020 23:36:04
avatar
572 forum posts
420 photos

Neil,

I see that I should have read your thread before posing my own questions about the fairings. Thanks to Chris and Gordon for the clarifications!

Any progress on your build yet, Neil?

N Pritchett03/02/2020 08:33:11
21 forum posts

Hi Steve,

Progress has been slowed due to life’s unexpected turns intruding into model building time.

Anyway, continued research into the fairings led me to the basic thought that, aerodynamics and functionality of the actual plane, mixed with common sense manufacturing methods used way back then, determined the final shaping. I then knocked up the shape with DevFus Foam. To do this I used the shape of the formers in the short kit as a starting point.

I needed to add additional formers for DevFus to blend correctly. I then changed the F9 & F10 formers, along with the ones I added from F8 to the tail at 50mm intervals. These were tweaked to give fair lines to the fus’ skin.

This gave me the visual 3d model that I could spin round and look from all angles matching the real life photos available. The formers were further modified so the model matched as closely as possible when compared to the “walkround’ photos available on line.

This may seem like a waste of valuable building time, but satisfied my tendency to be a perfectionist in intent (although rarely achieved).

I suppose it also gives me a possible foamy ducted fan build in the future!

Edited By N Pritchett on 03/02/2020 18:02:10

Steve Houghton04/02/2020 13:10:36
avatar
572 forum posts
420 photos

Neil,

I wasn't familiar with DevFus, but having looked it up I can see that it could be a great help to visualising the finished result. Thanks for the update.

N Pritchett04/02/2020 14:34:15
21 forum posts

Me being a fully fledged 3D cad man, I wouldn't particularly vouch for the ease of use of DevFus Foam, but it does have some nice features. I don't find it as easy to use as led to believe from the publicity.

Anyway, it served a purpose here.

The thing I took note of most was the change in fairing line along the tailplane abutment face; the change in angle where a typical elevator hinge line would be. I also deduced that the fairings, for the most part, are virtually parallel so they merge into the fus' skin naturally at their leading edge.

Another part I'm pondering over is if it's worth having an air passage through the fus' to avoid the flat nose airbrake! Fairly easy to make way past the battery area with the use of suitable batteries as there are so many shapes to choose from these days.

I'm looking particularly at the 'Airsoft' batteries that are 10x21mm cross section per cell at 2000mAh. I'm using 2 of these in the nose of my own design sloper where the 20x21 combined cross section goes well into the nose area.

With modifications to the existing battery box (don't use solid front) the slim batteries would easily fit either side, leaving the middle clear for the airway.

BTW what's the idea of the 6mm holes in the sides of the battery box? Is it for some dowel arrangement to stop the battery sliding out in flight?

Martin Gay04/02/2020 15:03:57
avatar
381 forum posts
254 photos

Neil,

Quite right! The holes are for dowel or velcro to prevent the battery and packing from moving backwards in flight.

Martin.

N Pritchett04/02/2020 15:22:19
21 forum posts

Cheers Martin.

Thoughts about the value of the air passage through the fus'?

Looks like it would trump trying to make cleaner servo exits, control horns etc. although I may try to keep the controls within the airframe but it's a lot of hassle, especially as my model isn't likely to rank highly in the scale ratings.

Andy Meade04/02/2020 15:29:05
avatar
2760 forum posts
717 photos

Generally not a great idea to pass the air through - you'll more than double the "wetted" area with the skin inside plus all the gubbins therein. They fly just dandy with the blocked off nose yes

Edited By Andy Meade on 04/02/2020 15:29:20

Martin Gay04/02/2020 15:35:16
avatar
381 forum posts
254 photos

Keep it closed.

The prototype model has flown (just) in 12mph winds on the Great Orme up to 45mph+ winds on the Lleyn Peninsular with the nose blocked off!

N Pritchett04/02/2020 17:17:36
21 forum posts

Thanks for the advice, will keep it closed.

For interest, how can the drag from increased wetted area be compared to the blunt nose drag; where presumably the laminar flow along the fus’ will be seriously compromised?

All Topics | Latest Posts

Please login to post a reply.

Latest Forum Posts
Support Our Partners
electricwingman 2017
CML
Sussex Model Centre
Slec
Sarik
Advertise With Us
Latest "For Sale" Ads
Has home isolation prompted you to start trad' building?
Q: The effects of Coronavirus

 Yes - for the first time
 Yes - but Ive bashed balsa before
 No - Ive existing projects on the bench
 No - Im strictly an ARTF person

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us

Magazine Locator

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

Find RCM&E!