QJ

Thanks for the info W8ye,

I have ordered covering: Profilm (Oracover?) transparent orange (54 g/m2) for the leading edges and underside, with ProLite (Oralight?) transparent white (36 g/m2) for the trailing edges and topside. The full product spec is here:

http://www.oracover.de/?content=down...=get&id=82

I ran up the OS FS-30S engine today on the bench with a 10x5 prop - I reckon I might get 18-20 mins duration from a 6 oz tank. Started first time and sounds sweet at idle or full throttle. It's my first I/C engine and was not quite as messy as I expected - just a little fuel dribbling out of the carburettor and greasy exhaust.Will post video link later.

QJ<br type="_moz" />

w8ye

My Feedback: (16)

Sounds as though it is going to be a nice plane

mike109

G'day

Sounds like the LT 25 is coming along well. My first four stroke was an OS 26 Surpass which is the older brother of the 30 you have . They are really sweet running engines.

I used mine in a Dynaflite Butterfly and I was worried that it may not have enough power for the large model. I need not have worried. It used to putter away and float the big model into the air and as you say, the little four strokes are really fuel efficient. Quiet too.

My LT-25 which is in semi retirement at the moment, had a Magnum 30 four stroke and it was great. It would fly for ages with quite a small tank.

Have fun. I am sure you will.

Mike in Oz

PS I picked up my latest OS engine today. A 120 AX. This is really out of character for me as a am mostly a four stroke person these days but it was going cheap, came with two mufflers (original and Pitts type) and did not cost a great deal. I was impressed with one I saw running recently. It was surprisingly quiet and had LOTS of power. We shall see.

Mike

QJ

120 AX must be a beast! What's it going into?

I was a little worried about going for a four-stroke with less power than the 'typical 25' for the LT-25, so your experience is quite a relief. I was in the LHS with my old dad today and he kept asking why I didn't go for the '40'. I just had to grit my teeth and hope for the best.

We got the engine mounted on a stick for running in - just tried posting avi but not accepted . Running time was 30 mins, over the whole speed range and running quite rich. Should give nice long flight times.

EDIT: Just added the video to youtube - it's not much but it amuses me:<span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; font-size: 13px; font-weight: bold; ">http://www.youtube.com/watch?v=Un7_34iZ94Q</span>

QJ

mike109

G'day

At the moment the 120 will be going into a box. It had been sitting for some time. Its previous owner was our club president but sadly about 6 months ago he died suddenly and unexpectedly. He had a VAST collection of planes, engines and other stuff and the club has been selling it off for his wife. The AX120 was the last engine to go. It looks like it has had little use though it has had some. It came with an original OS muffler and also a Pitts type mufffler which I noticed has been repaired with TIG welding. The motor looks perfect. I even had a look inside and things look fine there. I do have a Sig 1/4 scale Extra which I bought in a fit of madness. I think the 120 might end up in it but not for some time.

People mostly overpower models. If a 40 is called for, it gets a 46 or 55. It is a natural human reaction to think that if enough is enough then more must be better. Why use 10% nitro when you can get 15 or 30? The models I have which fly best are not the overpowered ones. I have a little 80% AstroHog which has a Saito 40 in it. It is an almost perfect plane to fly. It won't hover and it won't win any races but as a model to fly, it always puts a smile on the flier's face. I also have a Sig Four Star 120 with a Saito 150 in it. It is nice to fly but no better than the little Hog.

We flew my LT-25 with a series of engines. We started with the ASP 30 and it was perfect but then after one of its many crashes we put a Leo 46 in it (no nitro). It did fly faster but it did not fly better and spend most of the time at about 1/3 throttle. We also tried an LA 46 (just because we could) and it was similar to the Leo though slightly less powerful. I also have an LT-40 which originally had a Saito 56. It was perfect for the plane. Later I needed the engine for something else and I pulled the Saito out and put a Saito 72 in. It was madly overpowered and not very nice to fly as a result. Heavier too. It was faster, it took off more quickly but as a plane to fly, it was a bit of a handful compared to when it had had the 56.

Keep having fun and reporting your progress.

Cheers

Mike in Oz

w8ye

My Feedback: (16)

You will really like the OS 30 FS

QJ

Oh I forgot to mention before: I did order the OS radial mount set for OS FS-30S (part number: 71908300). It arrived too late for the LT-25 as I had already drilled the firewall for the Irvine mount, but I thought I would post the weight anywayas I was unable to find it anywhere online when I looked.

For comparison, the stock LT-25 two-piece nylon beams are 45 g, the Irvine 1-piece mount was about 41g (trimmed down to 36 g), and the OS aluminium mount 71908300(with tapped holes) tips the scales at 35 g. I was amazed. If I had the patience I would have waited, as my drilling of the redIrvine mount was not my proudest moment. Also as you would expect, the OS mount provides unobstructed access to the throttle on this four-stroke engine, whichcan bea problem with the stock SIG mounts.

QJ
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mike109

G'day

OS and Saito both make excellent metal mounts. I have used a Saito mount for my Saito 40a and it really runs well in it and I have used an OS 91 Surpass mount for my Saito 100 in my Decathlon. The OS 91 and the Saito 100 share mounting dimensions. I like my OS four strokes (40, 52, 81 Alpha, 160 Gemini) but I like my Saitos better. A Saito 30 would also have been excellent in your LT-25. I have one and I also have an LT-25. Perhaps I will unite them one day. The 30 is now in the Dynaflite Butterfly where my OS 26 Surpass used to be but I haven't flown it yet. I am currently getting it ready to fly.

Cheers

Mike

QJ

Maybe I should have gone with a Saito 30... but I never knew they existed until about a year ago, whereas OS have always been there it seems. And I'm not sure about the angled pushrods! Nobody ever has a bad word to say about them, so I'll probably give a Saito engine a home in my next project. And I really love the twins - just not sure I could fork out &pound;500 for the FA-60T. One day maybe...

QJ<br type="_moz" />

w8ye

My Feedback: (16)

I sold my Magnum and OS 30's. I still have my Saito 30's. They are sweet hearts

wazzbat

All this talk about four strokes is making me thinks I should spend a little more and get a Saito for my LT-40 and MidStar 40???

w8ye

My Feedback: (16)

I have over 30 Saitos and have a half dozen OS four strokes

mike109

G'day

My LT-40 currently has an Irvine 40 Diesel in it but that is just a temporary thing for a particular Diesel Fun Fly that I went to. It will eventually get a Saito again - possibly the very old Saito 45 which I recently upgraded with a new cam. Yes, I think that is exactly what I am going to do. It will not be a powerhouse but Kadets don't need lots of power to be fun to fly.

I did forget one OS four stroke that I have and I ran it yesterday for the first time. It is an OS FS 60 - OS's original four stroke from about 1975. It ran well though I am having some problems tuning the low end. I think I have the needle tuned in too far as it is restricting the movement of the carby barrel. I was considering putting it in one of my Kadets but it is a very large engine for its displacement and quite heavy too and there was not enough room between the bearers in the plane. The carby is also fixed and the controls would have been on the wrong side so I gave up on the idea.

I also have a Mid star, and some Four Stars - 40, 60 and 120. The Midstar has an OS 52 Surpass (very nice), the Four Star 40 has a Saito 62 (perfect), the Four Star 60 has a Saito 100 (grunt) and the Four Star 120 has a Saito 150 (lotsa grunt). I think my Saito count is currently at 14.

I have one Saito twin and one Saito radial. The twin is a 90TS and it is in a Goldberg Anniversary Cub. I ran it last Friday and was hoping to fly it on Sunday but I was not feeling well with the dreaded flu and it stayed in the car. My 90R3 radial is in a Hanger 9 Sopwith Camel but is yet to fly. It runs really well on the test bed but I think I will fly it in a Kadet Senior before trying to fly the Sopwith.

You have a long road ahead of you. There should be a few Saitos on it.

QJ

I covered the rudder this evening using my (clothes) iron - smaller covering iron is in the post.

The transparent white seems quite... erm... grey and nondescript but I think it'll be ok when its all covered with orange up front and orange trim lines. I think I'll use the LT-25 decals on the fin too. I used 'Balsaloc' on the wood first and it does help I think to grip the covering when you stick some heat on it.

It's not the neatest but it could have gone a lot worse! I'll tackle the fin next - should I do it in one piece (wraparound) or in two pieces?

QJ<br type="_moz" />

GaryHarris

I like that look! It's natural.

I did the wrap around on mine. I think its easier.

QJ

After using Balsaloc and heatto stick the Prolight/Oralight to the rudder, Iread the covering instructions. Apparently there's a thin transparent protective film attached that Idid not notice . No wonder the 25&micro;m film seemed so sturdy!

I'll have to remove the scrapfilm from the rudder and do it again. At least Idid not waste a bigger area. Ireally should read first and do later. It will probably work out a little more transparent when done correctly. And will probably stick better once Iconnect with the adhesive.

QJ

GaryHarris

Well it took me a month and a half but besides some tweaking here and there, she is ready to go.

wazzbat

Very Nice!  I'll be picking up my workbench today.  Then I just need to sand it and oil it.  Then to clean out the shed and start on the LT-40!  Not sure about what colours I'll use but I like what you've done with your plane!

GaryHarris

Thanks wazzbat. Up close the plane is far from my best build, but it is straight and should be easy to see in the air.

QJ

Looks really good biff - fast work.Keep us involved.Have you run the engine yet?

I have covered the fin now and it looks great. I plan to put white on top of the tailplane and orange underneath. The white covering is semi-transparent so you don't see much through it.

EDIT:I did the elevator this morning and got too much air stuck inside the air pockets. I had to use heat to un-stick a part of the edge to get a blade in and let the air out. Quite stressful. Looks ok now though. I was so tempted just to stick a needle in it but I guess that would be a bad idea with so much tension in the stretched covering.

Can anybody advise: should I use dope underneath fuelproof paint, or just paint directly onto wood (balsa/ply)? The SIG manual recommends to paint straight onto the wood - is this right?

QJ<br type="_moz" />

QJ

Not much time! I covered the wing this weekend - total weight is 480g. The oracover/ultracoat is really easy to use - I thoroughly recommend it.

The wing is much stronger now with the covering in tension, and easier to handle without turning to matchwood.

Update: the rudder is now hinged (sweat!) but the other control surfaces are still held on with sticky labels. Engine bay is fuel-proofed and I don't think I will bother with orange paint.

QJ<br type="_moz" />

wazzbat

I like that colour better!  Looks good!  And I was just searching around for the best covering to use?  I might have to see what other people say about the Ultracote?  Cheers.

GaryHarris

Nice!

LargeScale88

Nice covering scheme!!!!

GaryHarris:Hows your LT25 coming along?Have you started working on a new one yet? I'd love to see a new one you could wip up real fast because your already built one.

andrew66

nice job on the 25! I built one a few years ago (i think my build thread is in this forum) I bet if a guy had nothing but time, he could build one in a matter of a couple days. They are a dream to build and fly. I learned on mine. I originally bought a 25 for it, and it was enough power to fly it. The engine crapped out on me, so i bought a webra 40 for it. Was definately lots of power, but i could throttle back and just putt around. One thing i would have done differently would be beef up the landing gear mount and use nylon bolts. I had the gear depart the airplane a few times when i was learning to land.
Reading this thread has me wanting to build one again.