I'm scratching the Ag Cat 164B Turbine. I have this photo.

I'm seeking help with the engine choice? I know nothing of the newer engines available today. Absolutely nothing.

The span is 80" and the cord is 9.5"

Fuselage length should be around 55" or so, but I may extend it a few inches. This math gives me a scale of 1/6.

The aircraft is simply the Ag Cat with a replacement engine up-grade to the turbine.

The nose moment is long so weight is a factor, but I need power and torque.

The model will be 4" wide at the firewall and sport a 3" spinner.

I haven't determined weight? Possible suggestions?

I have builders plans partically drawn and an airfoil choice.

I'm not locked in, but I'm thinking a 2 stroke OS 120 AX. I'd also like to sport a three blade prop for better scale appearence.

Any interest, suggestions, guidance or help will be appreciated.

Thanks in advance

Charles

120 should power it just fine, if you keep it around 15lbs or so

How much can you afford to spend? The Wren 44 turboprop would be absolutely perfect but pricey.

With the long, thin cowl how about a Saito 200 inline twin? - John.

How about an RCV engine? If you're not familiar with them, the prop shaft is on the end of the cylinder sleeve, which rotates around the piston. The intake, glow plug, and exhaust line up in sequence with a port that also is part of the cylinder sleeve. The cylinder is actually pointed toward the front of the plane, so there isn't anything to stick out except the exhaust. The other thing about this engine is that the prop turns at half speed to the crankshaft, so you can use a larger, higher pitch prop. Look at www.rcvengines.com

<<How much can you afford to spend? The Wren 44 turboprop would be absolutely perfect but pricey.
With the long, thin cowl how about a Saito 200 inline twin? - John.
>>

John,

Thanks for your interest and response.

I can afford to spend whatever is necessary. I actually owned a few airplanes for a period of time, the last being a Lake LA4-200T. I also have five aviation ratings. You know what they say, "That was then this is now."

The Wren, although not a bad idea, is too large an engine for this model. Or , at least, I believe it is? I see no performance information or specks at their website? I don't want to increase the size of this model. At 80" and with two wings, this model is large enough, at least for me. The Saito 200 inline twin is also a 4 stroke. Two many moving parts and no information on HP in their website.

KH,

<<How about an RCV engine? If you're not familiar with them, the prop shaft is on the end of the cylinder sleeve, which rotates around the piston. The intake, glow plug, and exhaust line up in sequence with a port that also is part of the cylinder sleeve. The cylinder is actually pointed toward the front of the plane, so there isn't anything to stick out except the exhaust. The other thing about this engine is that the prop turns at half speed to the crankshaft, so you can use a larger, higher pitch prop. Look at www.rcvengines.com>>

I have no issues with someone re-inventing the wheel, but I'm a bit of a triditionalists. Or at least till I see proven use and performance, which I don't. Unless I'm not looking or reading in the right areas. I've never known anyone with a RCV pulling their crate. It's also a 4 stroke and probably wouldn't deliver what I'm looking for? As I said, I really no little, but with information provided, changes and decisions can be made. I will dig deeper into the RCV. Nice consideration. Thank you for it.

Charles

Traditionalist or not, you may need to reevaluate your stance on 4-strokes. In the field of scale models, 4-strokes are the dominant engine type. Check out the models at TopGun and I think you'll be hard pressed to find a 2-stroke. The two main reasons for this are: 1) thrust and 2) sound. A 4-stroke engine, while not running at the same RMP of a 2-stroke, is nevertheless capable of producing more prop-turning torque.

And a good 4-stroke (for example, from Saito or OS or a Laser) is as reliable as they come.

Also common wisdom would probably say that for an 80" biplane you'll need at least a 90 class 4-stroke and for anything approaching aerobatic performance a 1.20. You might want to have a look at the Saito 100, 123 or the newly introduced 115.

abufletcher,

Your information will be digested, thanks for the reply.

I already own a Enya 1.20R 4S and a 1.20 4S. Plus an OS 90 4S.

You may be correct in what you say. I strongly believe the 1.20 just isn't enough engine for a bi-plane at 80"?

I may be incorrect, and I'm fully open to conversation and suggestions.

Keep in mind the long nose moment. Last thing I need is to add addiotional weight to the tail for balance.

4 Strokes? OK, who makes the lightest and most powerful for this particular application. Don't forget my interest in a three blade prop.

Your help is appreciated.

Charles

I suppose it depends on the biplane. I do WWI and my next model will be a 85" biplane (Albatros CI, two-seater) but WWI bipes had a very light structure. The Ag-Cat 164B is obviously a much more substantial aircraft and would be expected to be a bit more aerobatic. Still, I can't imagine that you'd need more than around a 125 to power a model with scale flight capabilities.

All the more reason not to over-engine your model.

I'm a Saito fan, myself. Good, strong, reliable engines with a sweet, sweet sound. Be aware that you won't be able to swing a scale diameter 3-bladed prop on ANY traditional 2- or 4-stroke model engine. However, with it's novel design the RCV engine can turn a much larger diameter prop.

http://www.horizonhobby.com/Products...rodID=SAIE125A

Based on Bipes I've had in the past, it would be pretty hard to keep at 15lbs with an 80" wingspan (but not impossible). That being said, I would consider a saito 150 or maybe a 180 which would give a fair amount of reserve. A larger engine would give you the torque you would need to swing three blade props. A buddy used a 150 to swing a 16x8 three blade grupner prop that looked real nice. I used a saito 120 on a 14lb Phaeton 90 with 4 ailerons. 15 lbs is about it for a reasonable limit for a 120 to have adequate power reserve, (with a high drag, lots of wing area design). It was by no means very fast as speed goes, but with 4 ailerons it would do the most beautiful slow speed aerobatics you ever saw. Loved it. Just my opinion.
Edwin

abufletcher ,

You're making a lot of since. This is why I ask questions and follow advice.

I took a look at the Saito engines. The 150 or the 180 may also be an attractive choice. Ever see them at work?

Did I mention the Ag Cat's wings are metal covered? I'll use balsa, but I am considering covering the wings and airframe with metal. I have a lot of experience working with metal.

[Quote.]

Based on Bipes I've had in the past, it would be pretty hard to keep at 15lbs with an 80" wingspan (but not impossible). That being said, I would consider a saito 150 or maybe a 180 which would give a fair amount of reserve. A larger engine would give you the torque you would need to swing three blade props. A buddy used a 150 to swing a 16x8 three blade grupner prop that looked real nice. I used a saito 120 on a 14lb Phaeton 90 with 4 ailerons. 15 lbs is about it for a reasonable limit for a 120 to have adequate power reserve, (with a high drag, lots of wing area design). It was by no means very fast as speed goes, but with 4 ailerons it would do the most beautiful slow speed aerobatics you ever saw. Loved it. Just my opinion.
Edwin.]

A good opinion it is! I mentioned those engine choices before I read your reply.

Can you tell me more of your buddie's Grupner prop? Does it resemble that of a turbine prop? I was considering a carbon fiber prop. I find NO measurements of any Saito engine. Would your buddy give them up to the 150? Be nice to have them, especially in locating the firewall.

This Ag Cat, being scale, with both wings sheeted, add "extras" for detailing not to forget glassing and paint, and it wouldn't take much to exceed 15 lbs, Especially if a fabric covered Phaeton came in at 15 lbs. Great model BTW. I once did Christen Eagle graphics for a customer with a Phaeton. I may have a photo someplace?

Here's a photo of Engine possibilities. I'll get the photo of the 150.

I do hope suggestions and conversations keep coming.

Thanks,

Charles

I have a 180 and four 120's, but not a 150. Alas, my buddy moved out of state about 4 years ago and have since not had much contact. But a 150 should be real close to a 120 in physical size. The 180 is not that much bigger than a 120 as far as length and mounting holes go. Naturally head height would be somewhat taller, but just a little. Grupner props can be had from here http://www.hobby-lobby.com/grprop.htm
I prefer them because of looks mostly, they have a good scale look about them and it worked fine on a 150 and a 180. Here's a pointer to some dimensions. http://www.horizonhobby.com/ProdInfo...der_Manual.pdf You can find saitos manuals on the horizon hobby web site. Look under the support tab for the engine and there will be a link to the manual. This manual covers the 120, 150, and 180.
I dont know about using metal. I know some people that had real good luck using Behr latex house paint in silver. Looked pretty good, I'm going to try it on my P-47 when its time.
Edwin

Forgot to mention, I like your choice for a scale project. I saw Gene Scaucy (sp?) fly an aerobatic routine with an ag cat bipe at a local air show. I imagine with all that lift it would be great for slow aerobatics. However, I'm more of a round cowl man.<g>
Edwin

<< Forgot to mention, I like your choice for a scale project. I saw Gene Scaucy (sp?) fly an aerobatic routine with an ag cat bipe at a local air show. I imagine with all that lift it would be great for slow aerobatics. However, I'm more of a round cowl man.<g>
Edwin >>

I understand your like for Radial aircraft. However, I already have enough models with radials, my list is a long one!

1/4 scale Mystery Ship, 1/4 scale Red Lion, a bunch of Gee Bee Z's from 1/5. 1/4 and 1/3 scale. Also a Gee Bee Y and a Sikorsky S-39. I have a modified Sterling Stearman I built over 30 years ago. None of this stuff in done! So I would say I have enough radial models. One more I forgot, I have builder plans drawn for a 1/5 scale Grumman F3F-1.

I wouldn't consider building the Radial Ag Cat. So, understandably, my desire for the Turbine is obvious.

I'm going to do more research into the offering of 4Stroke engines. I also hope I receive more input and suggestions.

Thanks,

Charles

Here is a great website for Saito - includes sizes, etc.
http://saito-engines.info/specifications.html

allanflowersm

Thanks for the response, intetest and help!

And thanks for that website/link.

Unfortunayely I hate that MM stuff, what ever happened to inches and decimals? [&o]

I gotta do it in inches! Anyone know the conversion? Something about .29?

Looks like the 180 could do the trick because it weighs LESS than the 150. How can that be?

Who are Satio's competitors and what do they offer?

I hope this thread doesn't end. I need the assistance and interest.

I know this Turbine Cat isn't all that popular.

Charles

Multiply mm's by .0393 to get inches. It's easy. Working in the metric system isn't that hard. It just takes a different scale (ruler). There are 25.4 mm in 1.00 inches.

BB

OR, do it the simple way.

http://www.sciencemadesimple.net/length.php

http://www.sciencemadesimple.net/weight.php

Edwin

Perhaps not. Look at the example models on the 44 turboprop page, none of them are that large & all monoplanes.

What may be an issue is weight, the 44 weighs almost 4 pounds & the turbine Ag Cat has a very long nose, not sure if it would need too much tail weight to make it all work.

I have flown in an Ag Cat, a radial powered 3 seater on floats here in Oz. I thought it was a great experience, my wife was not terribly impressed with the flight! - John.

John,

Honestly, the 44 Wren is too large an engine for the model size I have in mind. Too expensive, complicated, and costly to run. I'm trying to keep it simple.

Kudos on your Ag Cat experience.

I have time in a Stearman. About 40 minutes. Actually did one take off by myself but the pilot wouldn't permit me landing the craft. He did allow me to set up the approach but took control before flairing. Yes, I was nervous and a bit aprehensive. Cost me 200 bucks! That's probably why. This was Key West BTW.

I bought a seaplane, a Lake LA4-200T for a change in careers. I thought I could run a successful Seaplane Tour Company with it, in the Caribbean. Never factored in corruption.

Only thing the Lake got me was a commercial/high performance seaplane rating. Burned through $250K in the years I had it and never made a penny. I was doing tours of Palm Beach, buzzing "Mar-a-lago" just before I sold the thing. And that's the truth. I'm lucky my wife put up with it.

I have almoust 1000 hr in the left seat of various airplanes, including 377 hours in the Lake LA4-200T. Which was the last airplane I owned. I actually started flying in 1965, I sold the lake in 1996. I can honestly say I don't miss "real" aviation.

It's lonely to say the least. My wife flew with me only three or four times in the Lake. She didn't like the Seaplane. That's well over 336 hours of flying without the company of the most important person in my life. She did like the Piper 180 because that looked more like an airplane. We enjoyed the Piper together.

I always like to say "That was then and this is now." I never figured out why, probably because it doesn't mean anything or that much anymore. It's just what you "used to do."

I can honestly say, with almoust 30 years of on an off general aviation, I don't miss it a bit.

Nah, who am I kidding!

Hey! Let's not forget my thread, which is "now" and important to me.

Saito's compitition? What have they got to offer?

Charles

BINGO!

The YS 170. Who's using it?

Charles

A fellow club member has a YS 140 & it has been no end of trouble, a real PIA. I find this curious as the pattern flyers love them & competition flyers cannot afford unreliability.

This is the Saito I suggested, two cylinders in line so it's easier to fit in long thin cowls (like yours). I'm not a Saito groupie, I just use what works which is usually OS but most people I know with Saitos are delighted with them. John.

John,

The twin you suggest is, most likely, wider at the head, than a single cylinder engine. The engine will also be inverted. So now I have two cylinders to deal with and not one. Two plugs that can fowl and not one. Not to mention twice as many moving parts.

With all this said, I'm electing to deal with ony one cylinder. I'm currently thinking the YS 170 4S.

But it's a fine looking twin.

Thanks for the reply.

Charles

That's my impression as well. It's too bad it wasn't done as an inline. Also I've heard that it doesn't provide at much power as other 200 size engines. It looks totally cool but it probably more hassle than it's worth.

I haven't seen many YS engines at the field.

<<I haven't seen many YS engines at the field.>>

Possibly because of their cost?

Charles