Balsa bashing

[Brian Seymour]

Hello onetenor, I guess that they may be known as countersunk cups, the trade name is Bellville Washer, the ones that I have used have a slightly different profile but serve the same purpose.

[Rex Dyer]

Brian, hi from Australia

Belville Washers are not the same as countersink cups. Belvilles are a um er a flattened cone, for want of a better

description, intended to act as a type of spring-washer, whereas countersink cups are used on surfaces which can't be countersunk into the material (e.g. the cardboard stuff used in some car trim . My old MGBGT had 'em all over the place)

Cheers

p.s lovely work

Rex

[Brian Seymour]

Hello Rex,

Thanks for your kind words and the explanation, I can't think of a better description. I intended the washers to act as springs, the merits of using them have been discussed and pontificated to death but they work for me.

[Brian Seymour]

She really isn't far off now, should ready to take to the skies by the end of the day.

The cables for the rudder have been fitted and setup. The adjusters have been fitted on the servo side in order to keep weight away from the tail, it's a faff to adjust but shouldn't need constant tweaking. I have never had the cables pull through the crimped collars but couldn.t resist bolstering them with blobs of thick CA.

On the nose section, fitting the ESC and ducting to aid motor cooling is underway, nothing clever or ingenious is required as there is plenty of space. I want to duct the air from the chin scoop directly to the motor to ensure that air does actually flow around/through it rather than taking the path of least resistance and going straight through the firewall. The plan for cooling is to take air in from the chin scoop, duct it over the motor and ESC, through the firewall & fuselage and out through the back of the radiator (which has been blocked off) via a hole (or holes) through the root of the wing.

Once that's done there is just the balancing and securing of the rx pack and receiver to do - I've got be in with a shout of a maiden tomorrow.

The washers discussed in previous posts:-

Rudder closed loop (tail wheel needs adjusting straight):-

Closed loop adjusters in the fuselage:-

Planned ESC install although I'll see if routing the motor wires over the top of motor mount is neater :-

[Jon H]

Full marks to Brian for his successful test flight today

[RICHARD WILLS]

Tally Ho Brian! ( or whatever that is in Russian)

Looks prettty real with the wheels tucked up doesnt it ?

Nice job , Ive really enjoyed the whole story . Who makes those kits ?

Richard

[Brian Seymour]

Thanks Richard & Jonathan - Nostrovia!

She flies sweetly, the maiden was typically (for me) nervy and the landing was somewhat bungled but after a tweak or two on the undercarriage and tightening the motor screws she was ready to go again. Just as I was starting to enjoy the 2nd flight Jonathan kindly pointed out that the battery hatch had popped off, despite flying a few more circuits the hatch didn't pop back on so I swung her round for a landing, she came in sweetly for a nice little landing. I would have lined her up for another run after refitting the battery hatch but the handset started beeping due to a low battery. I'm sure that I could have borrowed the pack out of my Dad's handset but it had been a pleasant evening with my fellow fliers and I decided to call it a day.

I can't wait to send her skywards again, she has been a thoroughly enjoyable winter build and if this evenings performance is anything to go by she will be an even more enjoyable summer flier!

Next job is to fit magnets to retain the battery hatch, my elasticated chord prevented the hatch from blowing away but couldn't hold it firmly shut. She could also do with a set of exhaust stacks, a few wafts of weathering spray and, a few panels smeared on.

Thanks to Richard for producing such a sweet model, to Jonathan for organising our winter build and the rest of our build group for the support, encouragement and, top tips.

My photos don't hold a patch on the action photos that Jonathan kindly took but here they are.

Posing in the pits just before packing away:-

Pilot relieved that both he and the plane made it back to solid ground safely but narked that the handset pack wasn't charged:-

[Nigel Dell]

Very nice Brian! looks good having just recieved the Lavochkin from Richard this has inspired me to make a start asap, it is a nice kit!

[Brian Seymour]

Thanks Nigel, I'm glad that this thread has been inspirational. The Lavochkin kit has got some sweet details and has the look of a menacing airborne brute, all the best with the build.

[Jon H]

I finally got back onto the hurricane today and had a go at the retracts. My efforts were hampered by 3 individual broken wires in my retract air pump and a leak within one of the retract cylinders (thanks hobbyking).

But, with all soldered and the relevant O rings replaced the result was a good one

[Brian Seymour]

That's sweet how they operate one at a time and they move at nice rate.

The Yak is ready for action, the magnets hold the battery hatch tightly so with the elasticated chord I've got be in with a chance.

To fit the magnets I used a tapered reamer to make a couple of holes through the crutch plate and glued offcuts to the underside of the crutch plate to make the hole a recess. The magnets were glued into the pockets with CA which worked surprisingly well. To mark the position of the magnets in the hatch, the hatch magnets were placed on top of the crutch plate magnets and covered with paint and the hatch fitted, the paint transferred onto the hatch highlighting the exact position. Recesses were cut into the hatch with a scalpel, they came out slightly oversize so a strip of Solartex backing was used to isolate the crutch plate and crutch magnets, the hatch magnets were positioned on top of the Solartex backing, the recesses in the hatch filled with epoxy and then the hatch fitted. Once the epoxy cured the hatch was removed and Solartex backing removed - it came out just right.

Crutch plate with magnets:-

Magnets in the hatch:-

 

A couple of other pictures from the final stages:-

Air duct in the cowl for motor cooling, made from 1/16" balsa:-

Motor mount with ESC, also the hole through the firewall to draw the hot air our from the cowl:-

 

Edited By Brian Seymour on 05/05/2016 22:04:08

[Brian Seymour]

The Yak had a nice little outing at the club's Fun Fly-in on Sunday, I didn't use her to compete but a got a few flights with her after the competitions - the warbird fun started when the Fun Fly finished!

Jon took her up so, with a bit of luck, he'll divulge a technical and non-biased appraisal of the way she flies.

In the meantime, my biased appraisal is that she is superb! With 970W she has an abundance of power, easily takes off on 3/4 throttle, doesn't peter out on vertical climbs and W.O.T. fly pasts almost crick my neck. By the time I flew her the breeze had dropped just nicely and there wasn't much in the way turbulent air so she was responsive, stable and predictable. Big loops are a breeze, requiring a bit of right rudder to keep her honest on the way up and barrel rolls are easily executed. As it was pretty calm I didn't get round to landing without flaps but she lands easily with full flap in dead calm conditions, the half flap setting seems to make her balloon up when flaring. Flight time varies from 7mins for full on recreational flying to 10mins when pottering round between tricks.

The CG was set according to the plan and is just about right for me.

[Jon H]

She did fly very nicely when i had a drive around! The only thing that was a bit strange was that landing as i couldnt get into a nice 3 point attitude and ended up bouncing all over the place. I think my use of low rates might have been partly to blame. I would have had another few go's at it but our tank was running low on mAh so it was now or never. I did also find there was a large power/pitch couple when i went around after my first aborted landing with a very large nose down pitch moment when i opened up the power. but once up to speed this went away totally.

If it were me i would probably experiment with the down thrust angle a bit and perhaps move the c/g as well, but to be fair i am splitting hairs a bit as it flew very well.

Its all been a bit quiet on the hurricane front as i have been busy with other things and the work i did do (sanding, sealing things with resin, then more sanding) did not make for interesting photos. Last night however i did get the first layer of primer on the wings and hope to do the fuselage later today

[Jon H]

Finally, I have something to report!

The hurricane has progressed quite nicely and now has its tail/fuselage covered and tail surfaces glued in place. The wing has been sanded smooth and we are getting close to the fun part...painting..

I have also added some details to the cowling and added some imitation panels to the fuselage. These are too shiny at the moment but once painted, weathered, and then fuel proofed it will all be fine

[lightning 759]

don't know if I,ve missed it in reading some where but can you tell me the recommended electric set up please

andy

[Jon H]

For the Hurricane? no idea. Best plan would be to contact Richard at Warbirds directly

[Guy Pickett-Jones]

Hi Andy, Sure Brian will be able to give you a full break down of the electric set-up in his Yak. All the other Yak's in the club build are going IC I believe.

Back on the Yak myself now after having a break to do a re-build on one of my gliders!

Quick update on progress today - The new stage was to look at the retracts - so progress to day was starting to put the mounting plates in. With some careful marking out the areas were cut out and using the hot wire process the foam removed. As indicated in the plans the target was to get as much forward rake as possible - this hopefully has been achieved In doing this the retract units might need to be packed out as the units are quite deep and with the rake angle some 'potential' depth in the wing has been lost. I don't see this as an issue.

Some Oleos have been ordered and once they arrive I'll will plan out the exact position of the wheels. I know not everyone has but I do intend to make use of the vac-formed wheel well liners that came with the kit. I will however be using a 75mm wheel and not the 85mm as indicated on the plans.

Guy

Edited By Guy Pickett-Jones on 12/06/2016 23:29:51

Edited By Guy Pickett-Jones on 12/06/2016 23:30:34

Edited By Guy Pickett-Jones on 12/06/2016 23:31:06

[Brian Seymour]

Nice progress on both, Jon - the metal covering looks ace.

Andy, I guess that the recommended electric setup on the Yak is the same as the Spitfire but I used some kit kicking around from an airframe that I sold:-

• Motor - EMP 5055 580kv
• ESC - Hobbywing Platinum 100A
• Flight Pack - 5s4000mAh
• Prop. - APC-E 13x8

In the meantime I had a couple of exhaust stacks 3d printed (thanks to Richard and Glynn), the finishing process applied has nicely smoothed out the contour lines that 3d printing usually leaves. The contour lines are very faintly visible but I reckoned that it gave them character so painted straight onto them and glued them in:-

She has racked up quite a few flights now and she is still my current favorite, get them flying fellow builders - you're in for a treat!

[Jon H]

I'm working on it!

First layers of paint went on this evening

[RICHARD WILLS]

Hi Andy /Brian ,

We have had about ten of the Yaks flying in our club . All of the electric versions have been using a power train equivalent to a typical 1400mm FMS fighter.

Typically 600kv motor , 4s 3300 or 3700 pack of about 30c . Because all of ours weigh less than 5.75lb (brown paper covered) They have very sprightly peformance ,

Prop wise , we use ether the FMS prop blades screwed to a dubro spinner back plate , or easier still , use the Dynam Tempest prop and spinner.

I would think the Master airscrew would be similar performance . The above set up gives OS52 FS performance .

Keep it light for the best result. We have flown both versions together , That set up must give 0.8 hp !

Richard

[lightning 759]

Posted by RICHARD WILLS on 15/06/2016 08:48:52:

Hi Andy /Brian ,

We have had about ten of the Yaks flying in our club . All of the electric versions have been using a power train equivalent to a typical 1400mm FMS fighter.

Typically 600kv motor , 4s 3300 or 3700 pack of about 30c . Because all of ours weigh less than 5.75lb (brown paper covered) They have very sprightly peformance ,

Prop wise , we use ether the FMS prop blades screwed to a dubro spinner back plate , or easier still , use the Dynam Tempest prop and spinner.

I would think the Master airscrew would be similar performance . The above set up gives OS52 FS performance .

Keep it light for the best result. We have flown both versions together , That set up must give 0.8 hp !

Richard

Thanks for that Richard , its for the La7 getting close toi finishing now

andy

[Guy Pickett-Jones]

Hi Richard,

Only just heard about covering in Brown Paper technique - could you, (or anyone) give some advice? Benefits etc?

Also would this be suitable for an IC powered model - Still not sure which way to go covering wise with mine.

Thanks,

Guy

[RICHARD WILLS]

Ok Guy , I'll argue the case for brown paper covering . First of all Ive been making this size of fighter for 25 years.

Probably made more than you can shake a stick at ! I very rarely come across any of my customers who can build a lighter plane than me . Is it because I'm super human ? My wife assures me not.. Its humble brown paper.

So you get the cheapest stuff available (99p) from the corner shop (not Smiths) thats because the more sophisticated shops stock reconstituted paper , which falls apart when wet.

So lets say we start with the underside of the wing , Cut out the shape very roughly . Paste the matt side of the paper with PVA (not pound shop stuff) You may have to add 10-15% water to get a single cream consistency . Let the paper grow for a minute , then smooth it onto the wing with your hands . Then get your solarfilm iron out and iron it like plastic film . PVa is heat reactive so works a treat . Finish the whole plane as if solarfilming , the tail plane may warp a bit while damp but will soon dry out and bend back so just ignore it. The paper goes round convex curves superbly and the creases often just melt away with the iron .

When its all done , just leave for a day to really lose the moisture, Next day quickly brush coat with some dope thinned with cellulose about 40% . (not critical ) .

I then grey primer with a halfords aerosol , but any paint is ok from then on .

My original La7 built in 2003 eventually did over 1500 flights !! The only thing that happens was the firewall worked loose. I gave it away in the end as I was sick of it.

Maybe just try doing a bit of old balsa or an old wing , I will be surprised if youre not smitten.

Regards

Richard

[Guy Pickett-Jones]

Thanks Richard,

I might give this a go.

Guy

[Jon H]

I am going to try that on my yak when I get round to building it. Its very similar to using tissue paper (which I have done before) so I don't think its going to be any trouble

In the meanwhile the hurricane has progressed nicely with the undersurfaces almost all painted. I have also started painting the cockpit area and mounted the dummy exhausts on the cowl

For the exhausts I didn't just stick them on the cowl as the kit intends as I'm not a fan of that stuck on the side look. Instead I cut slots in the cowl and mounted the exhausts on plates glued inside the cowl. This enhances the looks and allows some cooling air out of the back of the cowling.

The wing has been painted on the underside and the decals applied. Some of the finish is not as a perfect as I would like but I have already spent more time on this than I should have so it will have to do!