Dad_Roman

Yea!!! Need the full specs on it!

That motor is a beautiful piece!

Hey Steve, you think that would hang on the front of a 100" Corsair?

Kmot

My Feedback: (24)

That thing is huge! It takes up the whole seat on that chair.

ulrich/Germany

Here you go, the German site is more actual but probably harder to read for you ;-)

http://www.modellmotoren.privat.t-on...ngl-start2.htm

Patxipt

Armin at its best!
I gotta start saving for an Armin de Vries engine

Gonzalo38

I'm looking at the possibility of buying the new Composite Arf 4FU Corsair http://www.composite-arf.com.hk/ar/Catalog?cat=44 and I've been told that the RCS250 radial is the best engine for this plane.

Any special thing I should know about this engine before making a purchase decision ? I mean...... is reliable enough ? Any issues ? Does it require a lot of maintenance ?

Thanks for your help.

Armin de Vries

Hello,
This motor has up to now still no name. I designed the motor in behalf for a customer. If someone interested in the motor I will built a serie of this motor.

(Sorry, my Englisch isn’t very good)

Armin

Gonzalo38

Does somebody has experience in terms of reliability with the RCS 215 and the RCS 250 ?

I've read that the 215 has been a more reliable engine and I wonder if that is related to the fact the it is a heavier engine with less HP than the 250.

warheadforever

Wow, what a peace of art! That thing is really nice!

cometravi

http://umsindia.com

chasrb

Ok, I had to do it here is an incredible 14cyl Seidel (you may have seen it tho)

[link]http://www.youtube.com/watch?v=1rBwKOdBLdQ[/link]

Okay I could not resist this post....
[link]http://www.youtube.com/watch?v=Vf8tx1js8VY&feature=related[/link]

chasrb

I have a friend who has a Technopower 9C for sale.
[link]http://cgi.ebay.com/RARE-TECHNOPOWER-9-CYLINDER-4-STROKE-RADIAL-RC-GLOW-ENG_W0QQitemZ150329978964QQcmdZViewItemQQimsxZ2009 0302?IMSfp=TL090302202003r37137[/link]

Armin de Vries

New 130 ccm 3 Zyl Radial first run

http://www.rcmovie.de/video/df685ed8...rster-Testlauf

Patxipt

Sounds great Armin! Another success!

Chris Nicastro

My Feedback: (3)

Ok maybe this is the best place to find an answer or direction at least.
I have a SisT FW190A kit coming soon so I'm planning the engine choice right now. I want a radial but I want GAS not nitro. Why? Because of the fuel wrecking my paint job. Ive consulted with an auto paint dealer her locally and said he has nothing to offer that would resist Nitro fuel very well. Thats another topic, the paint to resist nitro and get a scale look so I can just go with a nitro radial engine.
Back to the engine question, is there a gas conversion for an engine like the Saito 5cyl or maybe the ASP/Magnum or the Technopower 5th scale 9cyl engine? I need an engine smaller than about 9in in diameter is the problem and still have the power to fly a 25lb+ plane.

Any help would be really appreciated, this might be an impossible request unless I make the conversion myself maybe.

Chris

stevesak

My Feedback: (27)

Hi Chris,

The closest matches that come to mind are the RCS/Moki 150 cc on ingition. It is 10 inches in diameter (too large I suppose).

http://www.rcshowcase.com/html/RCS/rcs150.html

Again, back in 1995, Seidel made a 5 cyl 125 CC called the ST-525 both in glow (ST-525GL) and on ignition (ST-525-B). The B's had issues with the ignition modules and weren't very successful. They are probably about 9.5-10 inches also, so I'm still not sure if it would fit your application.

As seidel's emphasis seems to lean more towards gas on ignition today, they might be able to retrofit an ignition module for a 525 engine. They also will be offering a 160cc 7 cyl engine this year (per their website) with a diameter of 260mm, or about 10.25 inches. It is the ST-7-160-B.

http://www.seidel-triebwerke.de/deutsch/deutsch.html

Forest edwards made some 5 cyl gas radials on ignition, but again they are around 11-12 inches in diameter. Wally Warner was considering making a big 5 on ignition (protype was finished last I remember), but it is about a foot in diameter also. So I guess all of the current and past offerings are too large.

On to Glow...


A Tech 9 will pull about 22 pounds of weight with Nitro. I'm not sure how that will equate with gas...but at any rate, trying to distribute the spark on a ready-made glow engine would be a major undertaking.

The newest (indian made... only 1000 euro) seidel 70cc 7 cyl engine claims to be able to pull 14Kg, or almost 31 pounds... This might be your best bet as the diameter rolls in at just under 9 inches, but again... to distribute the spark... 7 sensors on the hub? Brand new backplate with a crank that gears down 2:1 for a more traditional distributor...... I dunno. I suppose this is your best bet if you are a good machinist. If the indian engines never ship, you should still be able to find a german made ST-710 to tinker with, but it will cost you almost double.

Unless there is something obscure out in europe that I don't know about (like Penta) you might be hard pressed to fullfill your requirement.

Hopefully someone can correct me or throw out some other options, but there are no easy solutions that come to mind. I hope this helps,

Steve

Thayer

RCS is going to be a bit tough. I thought of that earlier, and found this on their home page.
http://www.rcshowcase.com/

TBM is handling Moki in the US now.
http://www.troybuiltmodels.com/

Thayer

the Gnome

Hello Venomous,

a small electronic equipment factory here in germany, "Müller Elektronik", build spark ignition systems for radial engines with 1/4'' spark plugs. They are quite expensive, a 5 cyl. system will cost about 700,- Euro. How ever, when converting an engine from methanol to gas, You will need the same amount of oil.

The Seidel ST 710 don't needs nitro, so that Your scale finish might stand the pure methanol and 5% oil.

gnome

Holm und Rippenbruch

Chris Nicastro

My Feedback: (3)

Thanks guys for the suggestions. After some research I was getting the feeling like I was asking for a unicorn. It looks like the best compromise is the nitro radial after all. My focus will turn to the paint and fuel proofing solution.
Last night there was an interesting development. My very good friend offered to sell me his brand new Saito 325 radial.
Would that engine turning a Solo Prop (when they become available again soon) work well on the Sist FW 109A? They claim a weight of about 25lbs but I understand some have been as heavy as low 30's. Do you feel this engine will be a good match? I would like to run a near scale dia prop and I have ordered the scale spinner with the incorporated fan.
Can this engine handle a larger dia 3 blade prop than the specification 20in dia. I figure with the adjustable pitch I can swing a larger prop and tune the peak RPM and measure the thrust. I'm wondering if anyone has experience already doing that same thing and what are the results. I would think that 53cc and 5 cylinders would have very good torque to swing this. This will be my first radial so I want to wrap my head around them better.

Thanks!

Chris

Radial power

Well, I waited to see if someone had something to tell about this, but since no one answered, I'll write my opinion.

First of all: weight. I dug through several threads to find [link=http://www.rcuniverse.com/forum/m_2249190/mpage_1/key_/tm.htm]this one[/link]. It is about the OS FF-320, which is slightly larger in displacement and has less moving parts than the OS or Saito 5 cylinder radials, but the difference should be limited to maybe a few hundred rpm more.
This said, in that thread they mention a static thrust of about 22lb with a 20x10 prop (post #38). That kind of power allows a 19lb aerobatic airplane to go vertical without slowing down.
Now to your FW 190 and (hopefully your ) Saito radial: I said that likely the top rpm difference is only a few hundred rpm, so I'd say it's safe to assume that the radial would pull around 20lb static with a 20x10 prop. That's more than enough to fly a 25lb plane, but possibly enough even for a low 30s one. If I were you I'd first run in the engine on a stand and make sure that it's developing its full power before attempting a takeoff with the FW-190. Even then, to be safe, I'd try a 8 pitch prop for the first flights, like a 20x8 or 22x8. You would lose some top speed with such a prop, but it would allow more pulling power if needed. Later, if the airplane flies fine with one of those props, you can try more pitch.

3 balde prop: Well, as I said above, I'd take it easy during the first flights, so I'd start with a 2 blade prop and see how the propeller - engine - airplane combination behaves. Fact is that 3 blade props are less efficient than 2 blade props, and in any case, since they load the engine more, it's necessary to use a 3 bladed prop with a smaller diameter than an equivalent 2 bladed prop. So, if the engine is happy with a 20 or 22 inch prop, an equivalent 3 balde prop would be around 18in diameter. I wouldn't go any larger than that, and even 18in diameter could possibly be too large.
Don't think that adjusting the pitch is a safe way of using a larger prop: even if the engine does not bog down too much, you'd be running with such a low pitch that, while producing good thrust, your powerplant would not be able to accelerate the airplane to takeoff speed. It's like modifying the gearbox of a fullsize car so that the gear ratio of the first gear became something like 50:1 instead of the usual 4:1: you'd have tons of pulling power but you'd be basically standing still.
These little glow engines tend to be more rev-happy than comparable gasoline engines, and, as such, tend to have comparatively little torque. Radial engines are better than singles in the torque department, but still you can't expect a 53cc glow radial to pull a 26in 3 blade prop with a direct drive, for example.
There are only two solutions if you want to have a scale sized prop: use a static display prop and then fly with a smaller one, or fabricate/buy a reduction system for the propeller. The problem with solution 2 is that such a system has to be very small, light, has to have inline input and output shafts (not just parallel shafts) since it's going to be used on a radial and it must not reverse the engine rotation. I don't know of any sources providing such a device, but if you have a metal lathe and a milling machine, I think it could be built.

Finally, I don't know if the scale cooling fan could lower the engine performance by robbing a significant amount of power. I'd try the first flights without it and then see if there's any change when the fan is added.

Hope this helps,

Radial.

Chris Nicastro

My Feedback: (3)

HI Radial,

Thanks for the tips. I was thinking the same thing about this combo I'm looking at and for sure taking it a step at a time is the plan.
Are there any viable power boosting techniques or add ons that I can consider to help make more power wit the Saito radial? I understand the Keleo ring exhaust has helped the engine run smoother and a little better on power. My only change would be to relocate the exhaust tubes to the scale position for the FW190.
What about superchargers? Anyone fit one to a radial before or make one? How about any head or valve work to port match the head with the intake and exhaust and improve flow? I have done this on a smaller OS FS26 with great results and I even increased the compression, that engine just screams now. I changed the cam to the one used in cars which has a higher profile for longer duration.
I wouldnt want to modify this radial to the point of poor reliability I'm just curious if there are some tried and true tuning options that help get a little more power from this engine.

As for Props. I would probably try something from Zinger because of the selection and price so I can do some tests. They also offer a built up 3 blade prop and you can select the dia and pitch very easy. Ive used their assembled multiblade props before and they are nice and light. In any case your right I need to take it a step at a time and measure the thrust with each set up.

Chris

Radial power

I don't think that real bolt on supercharging systems for model engines exists (well, I have seen photos of one such unit intended for car glow 2 strokes, but it was little more than a joke...), but even if they did, would you risk your expensive radial just to get a few hendred more revs out of it? I would not. Changing cams would be less drastic, but you would risk compromising your idle if you went for a very hot timing, and the idle is one of the best (if not THE best) things on a model radial imho. Also, finding a higher profile cam for a Saito 5 cyl radial should not be too easy. Porting the cylinder heads could have an effect similar to a higher profile cam: better top end and worse idle. Raising the compression would be the best option of those mentioned, but it would involve some precision machining of the crankcase and/or cylinders. As I understand it, higher compression helps a model engine designed for nitro run well on lower amounts of nitro. However there is always the risk of detonation if the compression ratio is raised too much.
In the end, I think that all these possible methods involving modifications of the engine risk doing more harm than good, especially if you consider that many parts of the engine were designed with certain load figures in mind, and exceeding these values with modifications could lead to catastrophic failures. So my suggestion is to avoid this kind of modifications.

If you really need more power, the best option is a bigger engine, not modifications to a small one.

About props: as I said earlier, it's not a matter of finding a low enough pitch to have rpm and thrust with the diameter you want, you also need some flight speed! All the thrust in this world would be worthless if the airplane could not accelerate to takeoff speed!
If you really want to try a slightly larger prop, you could try lowering the pitch a little, but in any case I wouldn't go with less than 6 inches pitch (really stretching it). Even at this low pitch, I'd be surprised if the Saito radial could turn a 24in 2 blade prop at any reasonable speed, let alone a 3 blade one. As I said in the previous post, the only option for a functional, scale sized 3 bladed propeller with this engine is a reduction system.

Sorry if it sounds harsh, but it's better to say things the way they are, in my opinion.

Radial.

Chris Nicastro

My Feedback: (3)

Radial,
Your not harsh thats what you think and I understand that. I just want to get to the knowledge base and ask whats been done and what works. If nothing works and its just open the box and run as is well then thats that. As for pumping an engine I was talking more along the lines of what YS does with their 4 stroke engines but anyway I'll test the engine and benchmark it before anything else happens. I'll keep the planes contruction as light as I can too, every bit helps. I'll have to do a series of prop tests and calcs and figure out the best set up.


Chris

Radial power

I'm not saying that it's impossible to improve an engine in some way. I'm saying that the engineers that designed them already did a good job at extracting what power was available from the design. And while it's possible to improve on this for sure, there is a high risk that the end result could not be much better than the original (in fact it could even be worse). For this reason, I think that model engines should be regarded as "unpack and run", meaning no modification should be needed. Especially when the engine is an expensive radial .

Engines like YS and the old supercharged OS were designed from scratch with the supercharging system in mind, and as such, they are sized to take the additional loads imposed by such systems. Supercharging an engine that was designed to be naturally aspirated is asking for troubles and limited results.

Building the plane light sure helps, and you can take advantage of the fact that a radial does not vibrate much, so you can build slightly lighter than you would for a 50 or 60cc gasser.

Radial.

Chris Nicastro

My Feedback: (3)

Oh yeah thats right and I respect that the engineers have arrived at a suitable and sellable product. I also realize there is always a bit of over engineering that goes on to help reliability. Thats the unknown margin that all engine tuning eats away at, how much can I get out of it and how much can I get a way with. You can reverse engineer the product and make an estimate of the strength and therefore an estimate of the modification.
I dont intend to go that far. At the very least I would look in the intake port and see that the diameters match between the manifold tubes and the machined head port. You want that transition to be smooth and free of right angles and blockage. Same for the exhaust port. That just increases efficiency and improves flow so the engine will be more responsive and have a more complete charge in the cumbustion chamber. Thats what Ive done before on many 2 stroke engines and a couple 4 strokers. Engines are pumps so the better they breathe the better they perform. Just make it breather better and you will be surprised the gains that come from that alone. Thats before you increase compression or do any other timing tricks and tweaks.

Going to a radial from a 2 stroke gas engine to reduce vibration is another good point and exactly one of the reasons I'm going with a radial. I was just hoping to find a way to get the best of all worlds and have a gas radial that fits this particular plane. No nitro fuel to mess with and good power. Go bigger and its possible but the cost doubles!

So here I am back at gooey nitro but with a plan to make the paint resist it better. Fingers crossed.

Chris

Radial power

Well, if you really want to modify your radial and you know what you are doing, go for it. Just do it in small steps and every time check if the engine runs any better/worse than before. As I said earlier, I wouldn't modify a radial, but this is my opinion.

Now that I think about it, if I'm not mistaken, the Saito 325R5 radial uses five cylinder jugs from the single cylinder FA-65. If this is true and supposing that the cylinders used on the radial are identical to those used on the singles, we have that the ports and valves on those cylinders are already capable of feeding the engine at up to at least 9000 - 10000 rpm (the normal speeds reached by a four stroke single of .65 cu in displacement), way beyond the safe operating speed of the radial. So, if you wanted to improve the performance of your engine, I think you'd need to make the ports smaller, not larger. Cleaning up the ports should not hurt, but making them larger could. Just one more point to consider.

As far as paint, I have recently finished a model using Tamiya acrylic paint (I wouldn't do it again, but I wanted to try). It dissolves in contact with glow fuel, but I used a transparent poliurethane spray paint over the acrylic and it seems it is holding up well. I only use 5% nitro in that plane, but the paint job doesn't seem to be affected by it so far.

Radial.