I am thinking of building a K-F III this winter and am wondering if there is any reason not to use a Super Tigre 90 for power? It has 60 sized cases and weighs the same as a typical 60, so fitment, weight and balance will all be preserved. I have one 90 NIB and one used which is why I would like to use one.

BTW, I do know what the throttle is and that it works both ways, so I don't think over powering will be an issue. I want a nice, honest flying, simple grass field plane and the K-F should fill that bill very well.


Thanks,
Mark

[:-] The Kwik Fli is a relatively large a/c, for todays Radios and flying tecniques, so with proper engine management I do not see why not.
The only warning is relevant to possible Ailerons Flutter, as a friend of mine experienced on a Bar Fli, equipped with a YS 61. Other than that, enjoy!
Beppe

Thanks for the reply. I forgot to mention I will set it up with individual aileron servos in each wing panel, which will greatly reduce the possibility of flutter there. How are the tail feathers in this regard?

Mark

My opinion of a 90 in a Quick-Fli and especially a YS in a Bar-Fli.

Ray

What are you trying to say, Ray?

Mark

Looks like a totally normal C/L speed job to me.



A .90 is definitely "out of character," but as long as you build the airframe to withstand the extra stresses and speed there's no reason it won't fly.

David

Mark:
Just one word



[b]WOW[b]

It should have plenty of Get Up & Go!!!

Good Luck and Happy Flying

Peace

Mark O

-


I once arrived at the flying field and was handed a transmitter controlling a flying Bridi patternship and was told to "fly". So I flew out the flight and enjoyed myself thoroughly. After I landed the model and had it back safely in the pits, I was then told that instead of a Super Tigre G61 as it had the last time that I flew the same model, the model was now equipped with a Super Tigre G90. I would never have suspected that it was being powered by a G90.

Of course, I use mucho throttle management. Had I been the old fashioned type of flyer that used the throttle control like a toggle switch for either high or low power, I might have noticed the difference in power. As it was, I did not.

IIRC, the owner of the model used an APC 11x9 propeller. I wondered why the model was reluctant to land and that explained that.


Ed Cregger

I think the 90 would be good but you’ll need a pipe on it to help the balance and give it that extra punch.

mmattockx

It is interesting that people, looking for a plane for an engine they already have, they always want to choose a too “little” plane for that engine.

Why?
1 To be the most powerful pilot?
2 To show you can fly the plane faster?
3 To reduce the costs and the amount of material you can destroy?

When these are the reasons I have an advice for you.

Reduce the proportions of the Kwik Fly MKIII to 80 % of the original.
Then the engine is twice as big, the visual speed again a quarter more and de amount of material you use a half of the original. Typical Dutch thinking.

Cees

Without wishing to be at all offensive, this seems to be mainly an American thing - bigger, faster etc..

The most ludicrous thing I ever saw was a video of a giant scale B-29 doing high speed inverted passes at, I think, the Top Gun event. People have been hung for less [X(]

Ray

It's all just a part of our proud cowboy heritage.


Ed Cregger

Ed,

We in the Netherlands have to fit it in our little car.

Cees

We in America are reluctantly heading in the same direction.

Ever look at the carrying capacity of an SUV? No room for a good lunch, as far as I'm concerned. The wife and I drive minivans because of her business and my hobbies. My hobby of music/entertainment requires that I have enough space in the vehicle to haul amplifiers/instruments/PA systems around. Besides, the minivans we have get about 22 mpg, which isn't bad for the utility they offer.

Fortunately for me, I get a kick out of driving small cars. Unfortunately, with the oil situation of the past few months, their resale value has sky rocketed.

I drove a Subaru three cylinder five door for a while. Its only shortcoming was the lack of airconditioning, which, when you visit clients and must wear a suit, made the car impractical. That was in 86. Seems like yesterday to me. I liked the little Chevy Geo (Subaru). Its other shortcoming was a lack of sound deadening material. The road noise was almost unbearable.

I'm holding out for either a hybrid or an all electric car for local driving. By the time that I am ready to buy/replace the minivan that I drive, compressed air cars may be available. Not working full time any longer, I don't need a vehicle that is capable of crossing the country. Something with a 50 mile round trip range would be just fine for me. My days of playing music are just about over (arthritis), so I may not need a minivan after this one.

Anyway, there is always a work around for those with the gumption to find it. Lately, I've been getting interested in flying small IC and electric models, so my hauling needs are diminishing.


Ed Cregger

Ed my message was not as serious I did write. A little joking,
We have a Daewoo Nubira station wagon driving on gas (propane, butane), no petrol. So I can transport my planes easy. Gas is the cheapest fuel here.
For my work I often travelling by bike or train.
I want to delay my interest in the part of our hobby, electric flying, for a long time , nothing for a cowboy.(LOL)
Hope for you, you can make music for a long time. I like it too as an individual playing my accordeon.

Cees

I agree, put on the 90, pipe it and enjoy. Only problem swapping 60s for 90s is overpropping, e.g. torque and ground clearance. Use a 12x12 and have fun.

But, the KF III isn't even an aerodynamically slick design. It has a thick, constant-chord wing. If you're going for all out speed with a piped .90 turning a 12x12 why not build a sleeker model?

David

My reasons were:

1) I want a simple, fixed gear aircraft for sport flying off a grass field.
2) I like old time pattern aircraft and the way they fly.
3) I want to scratch build it and the K-F is an easy scratch build. I already have the plans in CAD format and I have a buddy with a printer to run them off.
4) The ST90 is really just an overbored 60. On a good muffler it is somewhat weaker than a piped Hanno Special 60.
5) All the current 60 size engines are the same size and weight as the 90 with less power. Why would I buy a new engine with less power and the same envelope dimensions when I have two already paid for and have run with excellent results?

I am not really a power mad flyer, I often fly at 1/2 throttle or less. In this case it just works out that the 90 will fit and balance properly and it is paid for. If I had a 60, I would use it instead. Simple choice...

BTW, the 80% K-F would make a fun 45 sized model. Or a rocket sled with the 90, even with that fat wing.

Mark

Mark (III?),

When you like the old pattern planes and the way they fly, how is it possible you are the owner of two ST 90 ‘s and not a G60 Blue Head.
Because with that you are a cowboy.

I show you a picture of mine, a special picture Ed likes I think.
Greets Baffle o Bill.

I bought the 90's before I had an interest in old time pattern. They are also a good substitute for the 60 sized side exhaust engines used in the early 80's, at an affordable price.

I may have been accused of being a cowboy once or twice in the past, but not with RC models. Not yet, anyway....[X(] It's all just fun and games, no matter how you cut it.


Mark

Mark,

You have my permission to build a Kwik Fly MKIII and powered with a ST 90
We like pictures of the building proces.

Succes Cees

Mark, I'm just giving you a hard time. We definitely want to see the build.

But, I would probably use this if I were to build one.

David

I had a ST90 in a calypso, it was fine except Landings were a bit hairy !!! with the big prop it would not land at idle, I had to kill the engine an glide in
or run out o fuel.

John

mmattockx

Supertigres are Italian engines. They need one blade every 5 CC (0.30 of a cubic inch) displacement you know. That’s a rule “As old as the way to Rome!” ( Did I read that somewhere before?) we all know in Europe.
In the past I always did use a one blade prop on the 30 , two blade on the 60, so you use a three blade on these 90's
So you can keep the pitch value low, of example 12 x 6 without making a lawn mower. (Kwik Mow Mark III) and reduce the speed and noise.


Cees

Well Mark, because in my view if you take the trouble to build a classic pattern design not only should it look like the original it should also fly like it. I don't understand why people take these old designs and start changing moment arms, control surfaces, undercarriage layouts etc. Worst crime of all is to overpower them in an attempt to make them perform in a manner for which they were never designed. In many cases these mods will certainly produce a better performing model but I think we should be trying to preserve these old designs "warts and all" and relive what it was like back then to build and fly these things.

Guess i'm just old fashioned in this respect. In the end it's only a hobby so everyone must do what ever turns them on.

Ray