Hangar 9 Ultra Stik 10cc

[Colin Leighfield]

While slightly indisposed because of my coming off worse against a Brewster Buffalo, I have occupied myself by putting this together. I just have the engine to install now. Reasons? I wanted a relatively large easily visible and robust sports plane to improve my flying skills. Also I wanted to have some experience with a petrol engine. I took to heart Bob Cosford’s observations after flying his Mustfire with the Evo 61 petrol that it wasn’t really worth the bother, taking everything into account. I still want to try for myself though and thought the best way would be a simple ARTF designed for a petrol engine. The Ultra Stik is exactly that, although designed around the Evo engine while I have bought the current version of the RCGF 61, slightly different. I’m aware of the concerns about noise with these motors, so will use an extension and secondary silencer.

[Former Member]

[This posting has been removed]

[Colin Leighfield]

Tom, thank you, carefully noted. At first inspection it all seems to be well glued but I will take another look at the wing mounting plate. I have epoxied the tailplane, so fingers crossed.

[Bob Cotsford]

I replaced the 1/4-20 threaded plastic inserts with good, British standard ( ) 6mm captive nuts on my H9 US 10cc as one of the inserts stripped. It was tight to start with, the bolts were hard to turn even after easing the holes in the wing.

I may have pushed the boat out a bit far on the power front, a Power 52 motor that I had lying about, an FrSky Neuron 80A esc and 6S 4000mAhr Lipo giving me 1400W to play with.

Apart from the wing bolt issue I've found it to be an excellent piece of kit both in terms of fit/finish and flying.

Mix the flaps in with ailerons for roll rate at low speed, mix the ailerons with coupled flap/elevator for silly loops and full span flapperons, crow brakes to stop it dead - it's a brilliant model for safely playing with mixing. The only thing that lets it down in the air is the coupling in knife edge, it's just plain hard work. On the other hand it's extremely tolerant on balance points, mine came out in the middle of the acceptable range after adding an oz or two of lead in the nose and it's so stable I intend to take some of the lead out.

Ali suggests .46 power and up so 10cc petrol should be fine. If one that has similar power characteristics to the Evolution that I had than a 13*6 prop should do the job.

 

Edited By Bob Cotsford on 12/08/2019 23:45:59

[cymaz]

Have you money in the budget for a good silencer. Any small 2 stroke can be very loud.

Tuning a petrol engine is very different to a glow. Once the engine has done something running, throw out the unbranded plug that arrived with the engine and put a ngk in.

[Colin Leighfield]

Bob, thanks for that, nice to know that you have one of these! The nylon inserts for the wing bolts seem ok, the bolts turn inside them easily and screw all of the way in with the wing off. I’ll take a good look though to see if anything is “iffy”. The advice on settings is also appreciated.

Cymaz, thanks also. As mentioned in the first post I’m conscious of the noise risk so am extending the exhaust into a secondary silencer. I have ordered the 60/120 size secondary from Just Engines and think that should do it. I note Bob’s suggestion of a 13”x6” prop, I might even kick off with a 14”x6” to keep the revs down, then take it from there. I’m not out for ultra performance anyway, just a reliable and robust regular flyer and petrol engine experience. I will get hold of an NGK plug as you recommend, I have used them in bikes for years and had good experience.

[Denis Watkins]

I did the same thing from JE Colin, and fitted using these clips of ebay, as they offer some insulation

[Colin Leighfield]

Thanks Dennis, I’ll have a look at those. Just got an email from JE to say they have refunded because not currently available. Wonderful! I have already got the smaller version but the outlet looks a bit small for this engine. More head-scratching.

[Don Fry]

Denis, what are those clips called?

[Denis Watkins]

Posted by Don Fry on 13/08/2019 10:21:15:

Denis, what are those clips called?

Don these, are cheap too

P-Clips 304 Stainless Steel Rubber Lined Pack Qty's 1, 2, 5, 10 P Clip Clamp W4

[Don Fry]

Thank you Dennis, ordered, and a problem solved

[Kim Taylor]

Try one of these:

**LINK**

I've put one on to my Wot4XL/NGH GT17 and found that it cuts the 'bark' right down, as well as 'silencing' a bit.

It's the one shown in the current RCM&E feature on silencing petrol motors.

I used a length of stainless steel flexi tube, joined with silicon tube to the engine at one end and the above silencer at the other.

Kim

ps Liking the look of the Stik - maybe one for the future - I'm fed up with Wot4's, even if you can get hold of them!!

Edited By Kim Taylor on 13/08/2019 17:53:29

[McG 6969]

... isn't your Fury build taking some 'delay' then, Colin? ...

Cheers, young man

Chris

[Colin Leighfield]

Kim, thank you for that. I have just read the article in RCM&E as well. I like the look of the Stik too, just a simple no-nonsense flyer and I take the point that it could be a substitute for the Wot 4! Somewhat up-market.

Hi Chris. It’s the time of year really and so much going on, not to mention my relative indisposition in the last few days! The Ultra Stik is a minor diversion and part of re-thinking what I fly to improve how I do it. The usual over-optimism of “knock it together in a day or so” looks more like a week, time has been wasted because of the complications of fitting the rear induction RCGF motor instead of the front induction Evo, but I’ve cracked that today

i’m happy with where I am with the Fury, getting the wings done made me happy and there are no imponderables as there have been with the Chipmunk, which I have also looked at again in the last few days. I was supposed to be in France this week on the Honda, but the damage to my arm meant I had to postpone, but I managed to move the whole thing, ferry crossings and hotels, by two weeks so I will be heading for Brittany in a few days. That will delay building by a bit more, but it's me being me and disappearing on the bike is something I like to do.

[Colin Leighfield]

In spite of Tom Sharp pointing that this plane is the “Ultra Stick” and not “Stik”, I note that I continued to repeat the mistake afterwards. Sorry Tom. Sadly I don’t know how to correct the spelling in the header, if any passing mod can advise it would be appreciated.

Now that I’m back in action I need to finish this to clear the space in the shed to get on with the Fury. It is a well made artf, but there is still a lot of work in setting it up. I have the radio sorted and the engine ignition set up. One of the toggle switches on the tx is acting as an ignition switch through an auxiliary channel and a Rexcel Opto engine killer. All of the flying controls and throttle are working. Also I have fitted a rev counter.

Because of the rear carburetter on the RCGF motor the engine sits slightly further forward than the Evo shown in the instructions. I have got this sorted out but it looks as if the c of g will be a bit forward of recommended as a consequence. To off-set this I have mounted the 4.8V ignition circuit battery at the back of the radio bay. Final judgement on c of g will be made after all of the detailed work is complete.

Rather than wait and find out that the engine is noisy I have worked on the basis that it will be. Therefore corrective action includes using the Dremel with a cutting wheel to cut two “V-notches” in the exhaust pipe and then hammer it into a 90 degree bend. I have pushed a flexible plastic extension pipe over the curve and will feed that into a secondary silencer. The best answer to reducing noise without excessive restriction is loads of volume. I have two options, I can’t remember where I got either of them and they’ve never been used. One I think is probably from JE, it looks like their 60 sized secondary and could be ok, but the outlet looks a bit small. The radical approach though would be to use the “tuned pipe” contraption, which is rather large but has loads of internal volume and good sized outlet. I actually think that it would look ok on this plane as well.Does anybody have an opinion?

[Bob Cotsford]

I used similarly styled tuned pipes on 61-90 2 stroke glows and found them to be very effective, for example an MVVS 90 was tested at 79dBa on a 14*8, I don't know the rpm but I'd guess around 8k. IIRC I used a 24" length for the pipe from the cylinder centre to the estimated max diameter of the pipe. I never did tweak it for maximum revs as it had plenty of power and good manners from the off. I once had a calculator for revs/timing/length but it was one I found on the internet.

The little tubby can does looka bit restrictive

[Colin Leighfield]

Thanks Bob, your opinion supports my thinking that the “tuned pipe” will do the trick. I actually think it could sound quite nice and should remove all of the “crackle” from the exhaust note. I’ll have the engine running this week, I’m looking forward to it. I should be able to fabricate a supporting bracket and fix it using the three undercarriage attachment bolts.

[John Stainforth]

The Ultra Stik was not designed around a gas engine: it came out way before gas engines became the new fad. In the US, Ultra Stiks and Great Planes Stiks (there's not much to choose between the two) are equivalent to the UK WOT 4's, and are at least as good. The classic weak spot of the Stiks is the rear fuselage because it tapers to a very narrow cross-section just in front of the tailplane, at a point where there are slots for the elevator and rudder push-rods. If the balsa in the rear fuselage is soft, there is a real chance that you could lose your plane to flutter. In the US most people beef up the rear fuselage of their Stiks with extra plywood plates etc, particularly when they put more powerful engines up front (usually, still glow, not gasoline).

[Colin Leighfield]

John, this current version is designed for 10cc petrol as well as electric or glow and is actually shown on the box and in the instructions with the Evo 60 petrol. Also the Horizon Hobby video shows Ali Maschinsky flying it with the Evo, with electric and a with a Saito three cylinder radial! Ali describes the background to it. There are a number of changes compared to earlier versions. Have a look at it on-line and see what you think. I bought it because I searched on-line for an ARTF for 10cc petrol and it came up immediately.

[John Stainforth]

Yes, it's a very versatile airframe that has not changed much over the years, and I am sure it would be equally good with glow, electric or petrol ("gas" power plants.

[cymaz]

I nearly bought the 30cc size Ultra Stick but ended up with the Wot XL.

[Bob Cotsford]

I've no idea where the 8k rpm came from in my previous post, I must have been dreaming when I wrote it as it should have said 10k rpm! If the 90 had only pulled 8k rpm it would have been a very sick puppy!

[Colin Leighfield]

Not sure I’ll be heading up to 30cc on anything soon Cymaz, although I did put an ASP180FS into a 56” span YT Ultimate biplane. A bit over the top and it proved it fairly soon by wrenching the engine mounting bulkhead of the fuselage!

Bob, I would never have questioned your accuracy! I think my OS91FX did better than 8,000 with a 16x8 up front, come to think of it.

[Colin Leighfield]

I have finished mounting the “tuned pipe” secondary silencer, I will be surprised if it doesn’t do the trick. Not a good solution for a scale model but it doesn’t look out of place on this. However noise certainly wasn’t a problem this afternoon because I failed to get a peep out of it! I have checked the ignition circuit and can’t find anything wrong. With everything switched on and the ignition armed, the Opto LED lights up and the tachometer also registers. Tanked up with E95 mixed with two stroke oil at 30:1 and the starter whizzing the prop round at a good rate of knots, nothing happens with or without the use of choke.

My usual first step with motorbikes is to get the plugs out and check for fuel coming through and for a spark. I couldn’t believe how hard it was to get the plug cap off to enable me to remove the plug! Eventually I did and the plug looked pretty dry. Checking for a spark, I couldn’t see one, although it is possible that I hadn’t pushed the plug far enough into the cap because I was scared I wouldn’t get it back out. With ignition armed, there is a “click” each time I rotate the prop, the sort of sound you hear when a plug sparks and it doesn’t happen with ignition “off”, so I think the electronics are working.

The fuel line was probably too long so I have shortened that and tidied it up. I will have another go tonight, but I have ordered a spare plug from Morris Mini Motors. Persevere! Any brainwaves will be appreciated though.

[cymaz]

If it’s a new engine the diaphragm may be so dry it has stuck. So first of all check that. Then the needles...make sure they are at factory settings. You could try the old trick of putting some fuel into the cylinder to coax it into firing. Can you see fuel coming up the line as you prime it?