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Nov 10, 2016, 05:57 PM
Registered User
Thanks, tomorrow is first flight....will post back as to whether its too heavy or not! The Laser 155 seems to have plenty of poke, I'm hoping it goes ok.
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Nov 11, 2016, 05:37 PM
Registered User
Flies good! Nice and slow on the approach, everything was pretty much trim. I do wonder if i need to improve the airflow through the cowling as the engine felt rather hot. Thinking on some ducting to direct air from both sides. Please with this one!
Nov 11, 2016, 06:45 PM
Late for work again!
Gary Binnie's Avatar
Thread OP
Excellent!

You could run the engine rich but it will make a mess. Is it new?

I flew mine with no cowling trying to get an ASP 120 two-stroke running properly, an OS carb eventually fixed it.
Nov 12, 2016, 03:05 AM
Registered User
When mine had a glow engine I cut a bit more out of the underside of the cowl, to make a larger exit for the air going through. If I remember correctly, I also opened up the openings in the front of the cowl a little.
Nov 12, 2016, 05:32 PM
Registered User
The engine is new, only 20 mins of run on it so far. Its a Laser 155. I think some sort of divider so that any air that enters the cowl gets forced over the engine, instead of around it should help. Spent a fair amount of time reading up on this. I run the old Irvine (UK versions) in all my other planes, mainly 53's and a 72. All dead stick a fair bit when running in, the laser however hasn't died once!!
Nov 13, 2016, 12:42 AM
Registered User
Monza Red's Avatar
You could try blocking off the left-hand air intake on the cowl.
Oct 03, 2017, 06:39 AM
Late for work again!
Gary Binnie's Avatar
Thread OP

Still plodding along!


Luckily I didn't say which winter I would build this in!!

Started this thread in September 2014 !

Noticed that the kit price has increased to 300 in that time, slightly above inflation!

The problem has been just finishing, a work colleague offered to spray it for me so the project is moving along a little bit.

I had already sprayed everything in beige high build primer and sanded that back, we have now sprayed white primer but there are pinholes and other problems which have to be fixed.

The pinholes are not fisheyes or any other paint mixing problem but where the glass cloth/resin is 'dry' in my attempts to scrape all the excess off. There are also some ripples in the wing veneer. My colleague, being a perfectionist (like me!), sent me away with orders to fix the surface before another coat of primer then eventually top coat.

I am using 'Etaglaze' putty, spreading it on very thinly with a credit card. Allowed to dry overnight (it actually dries very quickly) then block sanded with 500 and 800 grit paper. It looks messy but is very nice and smooth.

I'm keeping an eye on the weight, I can save weight in other areas (LiPo/LiFe Rx battery instead of Nimh and I'm not using the elevator joining wire or pushrod).

Back to filling and sanding, can't say I've ever spent this much time on finishing but there's no way around it.

Cheers

Gary
Sep 10, 2019, 03:00 PM
Late for work again!
Gary Binnie's Avatar
Thread OP

Still going!


Two years since I last posted and five years since I bought the kit!

The main problem has been finding fuelproof paint, I bought a tin of 2K white last week and sprayed a test piece which when cured did not mark at all with neat 10% nitro glow fuel (I usually use 5%).

I believe that the 2K that I used previously did not have the right amount of hardener. With this good news I am going to carry on and try to finish it.

One job that I had been putting off was fitting the wheel spats (pants). I bought them from Carbon Copy and according to them they are the right ones for an Xtra Wot (200 mm long) but with the supplied 87 mm (3.4 in) wheels the axle would be very close to the cutout edge.

I had a brainwave to use smaller wheels, I had a pair of 76 mm (3.0 in) wheels which don't look silly on the model.

There are no instructions for fitting the spats (there probably are with Chris Foss supplied items) but I guessed that they should be level with the fuselage datum. I marked a reference line around both spats and added a masking tape datum line to the fuselage.

Initially I went for an axle hole position in the middle of the cutout then noticed that more height is available with the axle slightly nearer the front of the spat. I will epoxy in some ply plates to reinforce the axle hole and use a second bolt to stop them turning.

Cheers

Gary
Sep 10, 2019, 06:26 PM
AndyKunz's Avatar
We all have at least one of those projects!

I've used 2K and it certainly is fuel proof. I'm running 30% but I don't try to spray raw fuel on anything ever. It's holding up for me. Not sticky, not peeling.

Mine is in the rattle can.

Andy
Sep 11, 2019, 03:08 AM
Late for work again!
Gary Binnie's Avatar
Thread OP
I have several of these projects!!

I always thought 2K was nitro proof as the Wots-Wot in this post is 2K and very fuel proof.

The penny dropped when we compared mixing ratios, what I wrote on the can with advice from the chap in the paint shop (Two parts paint, one part hardener, 10% thinners) is not how we normally mix paint at work (for reasons unknown).

Out of interest an Xtra Wot kit sold for 300 on eBay last week, perhaps the new owner will read this thread one day.
Sep 11, 2019, 01:50 PM
Late for work again!
Gary Binnie's Avatar
Thread OP
I was supposed to go slope soaring today (with gliders, not the Xtra Wot) but it was way too windy.

Have drilled all holes for the wheel spats, just need to sort bolts and axles for them.

One job I had deliberately left was the fuselage servo tray as there are two positions available for the rudder and elevator servos depending mostly on the weight of the engine.

I weigh my large models the same as full size using scales, I can go through the process if anyone is interested. An important part of this is the pitch attitude as it does change the results. The instructions say 'balance with the top of the fuselage level' which is a rare ambiguity. It could mean the top of the front deck, the top of the rear deck or the top of the sheet sides. The lovely fuselage datum line is not mentioned.

I've left a message on Chris's business phone and hopefully he will get back to me. Might be picky but I do want the maiden flight to go well!

Putting it all together for weighing showed that I have not thought about a propeller (but I have a spinner!). Found a 16x8 to use for the weighing.

It weighs around 5 kg (11 lb) with some paint and RC linkages still to add which isn't bad considering the whole model is glassed. CG is at 104 mm aft of datum (leading edge of wing at root) which is nose heavy, recommended CG is 112 mm or 100 mm without the wing. The nose heaviness will probably be the metal engine mount.

Another little job that I had to do was fit the remote glow bracket and wiring, only using this to avoid a hole in the right cowling.

Had a near miss at the end of the day when the wind pulled the fuselage out of my hands working on the garden bench, two minutes before it was sitting there on its own.

Getting there (I think!)

Gary
Sep 11, 2019, 02:08 PM
AndyKunz's Avatar
Quote:
Originally Posted by Gary Binnie
I weigh my large models the same as full size using scales, I can go through the process if anyone is interested.
We have it covered over in the Vanessa thread.

https://www.rcgroups.com/forums/show...3&postcount=39

Read the whole thread for the history to go with the spreadsheet.

Andy
Sep 11, 2019, 02:12 PM
Registered User
11lb is not bad. My electrified one weighs 10lb 10oz with batteries installed, which is a few ounces lighter than when it was powered with an OS120AX.
Sep 11, 2019, 02:19 PM
Late for work again!
Gary Binnie's Avatar
Thread OP
Will do, I use a modified full size spreadsheet, grammes instead of kilogrammes.
Sep 11, 2019, 02:27 PM
Late for work again!
Gary Binnie's Avatar
Thread OP
Quote:
Originally Posted by abenn
11lb is not bad. My electrified one weighs 10lb 10oz with batteries installed, which is a few ounces lighter than when it was powered with an OS120AX.
No one can match Chris's prototype weights,10 lb 6 oz he says.

My last Xtra Wot flew for a TV programme with an industrial radio pyro receiver/igniter and large flares taped to each wing tip, must have been four pounds extra. Worried that it was getting daft I refused a request to add a GoPro.


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