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

The Seagull has landed

Seagull Yak 54 - 90 size - SEA53B

All Topics | Latest Posts

Search for:  in Thread Title in  
Gary Manuel21/06/2018 18:29:10
avatar
1674 forum posts
1492 photos
Posted by cymaz on 21/06/2018 18:17:06:

Ah, the cunning plan comes to light!

No, the cunning plan was in case I needed to fit the baffling from the front - AFTER the cowl was in place.

I was going to glue some tabs with captive nuts onto the rear face of the outer rim of the cowl. Then I'd screw a circular disk, just the right size to fit the cowl opening onto the tabs. The disk would have had the required baffling glued onto the rear. Maybe I'll try this on another model some time.

Bruce Collinson21/06/2018 20:15:29
38 forum posts

Gary,

Meant to ask; are you proceeding with the standard alloy wing tube? The reason I ask is that as well as the muddle re the c of g, I picked up from an American forum that the tube is prone to bending in enthusiastic flight. I spent too long trying to source a carbon replacement but apart from a Chinese source (call me old fashioned, but ...) I couldn’t find an exact fit and ended up with a loose fit inside the alloy tube. Then, I couldn’t get a consensus from my elders and betters as to whether the carbon needed to be packed out and if so, with what. I’d be interested to hear your opinion on that. My amateur structural engineering instinct was that as soon as the alloy deflected by say 2 or 3 mm, the carbon tube would accept the bending load and the alloy would recover. BTC

Gary Manuel21/06/2018 22:59:35
avatar
1674 forum posts
1492 photos

Bruce.

I'm using the standard wing tube. I know a few people in the UK who have owned one of these models and have never reported any problems with the wing tube. I've even had a go myself and not bent one.

I'm no structural engineer, but I do know that close fitting tubes work by distributing the forces along their length. An ill fitting tube will only have three points of contact - one at each end and one in the centre. They need to be a tight fit along their entire length to work properly.

iqon23/06/2018 21:36:59
avatar
1345 forum posts
237 photos

Well done !!!wink 2

Paul Marsh23/06/2018 21:58:18
avatar
3257 forum posts
904 photos

I've got the other colour scheme one, with a CRRC 26 petrol, which is perfect for it. Am looking for this colour scheme, but not seen one. Inwood had the same one as mine, thought it was this scheme, but he can get one, so might call him to order on the next shipment, if one doesn't turn up at a forth coming show.

Want to do it in a JCB scheme, where I now work and where I've seen one at a Ashborne scale meet a while back...

Will use the new logo, similar to this:

dscf7465.jpg

Edited By Paul Marsh on 23/06/2018 22:03:47

Gary Manuel23/06/2018 22:34:48
avatar
1674 forum posts
1492 photos

Hi Paul.

Yes, I prefer the yellow and black scheme too. Available HERE for £174.90 including delivery!

Gary Manuel23/06/2018 22:47:19
avatar
1674 forum posts
1492 photos

Maiden today went very well. Model flies well although the elevator is a bit twitchy. Inverted flight also curved to the wheel side and it wanted to drop into a harrier a bit on landing. All point to CoG a bit too far back. Will try moving batteries forwards a bit.

Had a bit of an issue on the third flight. The canopy fell off in flight! I thought the canopy bolts may have worked loose. Turns out the ply tabs on the bottom of the canopy, that the bolts screw into had pulled out of the canopy - and no wonder. They were pretty much a butt joint with a short length of triangular balsa glued with PVA (or similar) onto the underside of the canopy. Took nearly an hour to find the canopy in the adjacent wheat field. A couple of puncture wounds in the wing covering where the canopy hit them, but no real damage and easily fixed (properly this time).

Gary Manuel23/06/2018 23:31:03
avatar
1674 forum posts
1492 photos

P.S. What's the JCB pilot doing in the passenger seat?

Bruce Collinson23/06/2018 23:36:14
38 forum posts

Well done Gary.

It is beginning to occur to me that, especially with ARTFs, anything which can fall off in flight will do so. I lost a canopy from an Extra (Great Planes) and the battery hatch from an Acrowot. You had a better day than me, I totalled a Wot 4 with signal loss. At least I can stop wrestling with it and it’s engine and crack on with the Yak, reinforcing its canopy tabs etc. Will you post the new C of G position in due course? Is the cowl ducting ok? BTC.

Gary Manuel24/06/2018 09:16:46
avatar
1674 forum posts
1492 photos

Sorry to hear about the Wot4 Bruce.

I'm not planning on moving the CoG very far. I might not even bother. It was quite windy when I flew it, which may have affected how it flies. I'll try again when it's a bit calmer before I decide whether to move it. Aim for the forward end of the recommended CoG range and you'll not be far off.

I'll never know whether the cowl ducting was necessary because I've never tried with out it. The engine runs nice and cool with the ducting in place, so it's staying.

Steve Hargreaves - Moderator24/06/2018 17:46:38
avatar
Moderator
6605 forum posts
182 photos

Excellent news Gary....glad it went OK. Does it have a tendency to flick if you apply too much up elevator at all? I had a smaller Yak54 which was a lovely flyer but would bite & bite hard if you were a bit rough with the elevator.....note the use of the word "had" dont know

What's the power like with that engine? Does it do nice "Up" lines?...big loops?

Gary Manuel24/06/2018 20:39:24
avatar
1674 forum posts
1492 photos

Steve.

It didn't flick on me, but I noticed that if I overdid the loops, it would corkscrew as though one of the tailplane sides was stalling.

Big loops and bunts were no problem with the power reserve I've got. I have a feeling that there is more to come once I find the right prop for it.

In my shed now - just epoxied the canopy tabs back in. Removal of the old glue didn't take long!!!

Bruce Collinson16/07/2018 11:07:00
38 forum posts

Gary,

Now I've finished repairing an Acrowot (u/c plate) and a Wot 4 (2 bulkheads, wing retention tabs etc) and have flyable go-tos again, I can turn back to the Yak which has been at a standstill.

May I ask, where's the c of g at the root? I might as well try for a good starting position the first time I fix the batteries etc. Thanks in anticipation.

BTC

Denis Watkins16/07/2018 11:24:27
2797 forum posts
139 photos

C of G is dead centre of the wing tube BTC

And on most models constructed that way

Gary Manuel16/07/2018 11:55:21
avatar
1674 forum posts
1492 photos
Posted by Bruce Collinson on 16/07/2018 11:07:00:

Gary,

Now I've finished repairing an Acrowot (u/c plate) and a Wot 4 (2 bulkheads, wing retention tabs etc) and have flyable go-tos again, I can turn back to the Yak which has been at a standstill.

May I ask, where's the c of g at the root? I might as well try for a good starting position the first time I fix the batteries etc. Thanks in anticipation.

BTC

Hi Bruce.

See the top post on page 3 of this thread.

I am happy with the CoG at 15cm from the leading edge at the wing root (7cm at wing tip), which is the forward end of the recommended range.

Posted by Denis Watkins on 16/07/2018 11:24:27:

C of G is dead centre of the wing tube BTC

And on most models constructed that way

Not quite on this model Denis.

My wing tube is 127mm from the wing root, which means that the recommended CoG positions are between 23mm and 33mm behind the wing tube.

Gary Manuel16/07/2018 12:03:44
avatar
1674 forum posts
1492 photos

I mentioned that my model was throwing the occasional tailplane stall at me. I've found the problem. The tailplane has warped since I built the model. I'm going to try and straighten it by the application of heat, possibly in conjunction with moisture / steam. If this fails, I may need to make a new tailplane but it will be tricky cutting the old one out.

I also have another problem. I noticed quite a bit of oily gunge inside the cowl from the beginning, which I assumed was oil from the exhaust being sucked back into the cowl. Eventually it showed up inside the fuselage so I had a closer look. I had forgot to put a tube onto the crankcase oil breather tube and vent it outside the cowl. blush. Major clean-up operation before I will fly it again.

john stones 116/07/2018 14:11:42
avatar
9557 forum posts
1428 photos

It owt to do with the braces ?

Gary Manuel16/07/2018 14:17:36
avatar
1674 forum posts
1492 photos
Posted by john stones 1 on 16/07/2018 14:11:42:

It owt to do with the braces ?

No. The braces were slack (neither pulling nor pushing) when I assembled the model and after the warp was noticed.

Edit - I did think whilst building and still think that it would be better with braces top and bottom, rather than just underneath, to allow both sides to be tightened till under slight tension. It would also allow the pushrods to be replaced by wires.

Edited By Gary Manuel on 16/07/2018 14:20:57

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! 

Email News - Join our newsletter

Love Model Aircraft? Sign up to our emails for the latest news and special offers!

Support Our Partners
CML
Expo Tools 14 July
Airtek Hobbies
Overlander
Slec
Gliders Distribution
electricwingman 2017
Wings & Wheels 2018
Sarik
Advertise With Us
Latest "For Sale" Ads
What is the main brand of transmitter you use? (2018)
Q: What is the main brand of transmitter you use?

 FrSky
 Futaba
 Graupner
 HiTec
 Jeti
 JR
 Multiplex
 Spektrum
 Other

Latest Reviews
Digital Back Issues

RCM&E Digital Back Issues

Contact us

Contact us