Posts: 2458
Joined: 11/29/2001 From: Pleasanton,
CA, USA Status: offline
I am looking to use the RCV 90 in my TF corsair. Like everyone else I would like to use a scale prop. I have read what Otto has said about scale diameter instead of blade count....but I would still love to use a 3 blader.
It seems the only 3 or 4 bladers used were Master Airscrew. I know they are expensive, but both Bolly and Mejzlik make carbon fiber 3 blades in 16X11 and 16.5X14. Bolly make 4 bladers in 15.5X12.5. Have any of these been tried? They can be found at [url]www.desertaircraft.com.[/url] TIA
Posts: 99
Joined: 3/8/2002 From: Universal City,
TX, USA Status: offline
Hobbsy:
I too have a H-9 P-51 that I am currently flying with a YS 91 FZ. I have been looking at the RCV at the suggestion of a friend. I looked at them today at my LHS and they look great. What size RCV do you have in your P-51 and how does it fly?
Posts: 99
Joined: 3/8/2002 From: Universal City,
TX, USA Status: offline
Sideshow and Jneesy:
I made a couple of posts on the "How to start an RCV" thread and the found this thread on four bladed props. I currently have an H9 P-51 with a YS 91. I have been flyin the plane with a Graupner 14X7 three bladed prop. I was looking for more realism so I thought I would give the RCV engine a try.
I bought an RCV 90 and have currently put about 1 hour and 15 minutes on it on the bench. The first three runs (15 minutes each, with complete cool down between runs) I started the engine with a starter using the spinner (didn't try the method suggested by RCV using the allen wrench). The last two 15 minute runs I started the engine by hand flipping the prop and it started very easily. As of now, I have run the engine at a max of about 3200 RPM. I plan to put about another 45 to 60 minutes on the engine gradually getting the RPM up to about 5,000. My plan is to install the engine on my P-51 and do some back to back testing (betweent the RCV and the YS 91). I just ordered some Zinger 16X10 three and four bladed props to try. I will also fly it with the APC 16X12 that I broke the engine in on. I will keep you posted on my tests.
Posts: 383
Joined: 11/25/2002 From: Arlington Heights, IL, USA Status: offline
Hello All, Is it possible....that there are no giant scale 4 blade props out there? Yes, Zinger make a giant scale 4 blade assembly, but the plate that holds the single individual blades is thick and heavy. So....help...... anyone. Where is the carbon fiber crowd?? I'm willing to pay custom.
Posts: 505
Joined: 4/11/2002 From: WimborneDorset, UNITED KINGDOM Status: offline
It is definately true that 3 or 4 bladed propellers are not as efficient as 2-bladed propellers, however with the SP series engines they can still be used successfully. I wouldn't recommend their use if the performance of the plane / engine combination was already marginal, but often a slight reduction in performance isn't a problem. Glass composite propellers are also more efficient than wooden props, so it would be worthwhile sticking to an APC or Master Airscrew type prop.
With regard to sizes RCV do not recommend the use of any prop (2, 3 or 4 bladed) with a pitch less than 10. 3 and 4 bladed props which have been tested by RCV and that are easy to get hold of from [url]www.apcprop.com[/url] 3-bladed props (APC) 60SP - 13.4x13.5 ; 15x13W ; 15x13.5 90SP - 15x13W ; 15.75 x 13 120SP - 15.75x13
Some of our customers have also used a 16x10 3-bladed master airscrew and have reported this to be good as well...In fact if I remember correctly this was on a Corsair.
Unfortunately I am unaware of any manufacturers who produce larger 3 or 4 bladed props. You could try [url]www.bolly.com.au[/url]
I have the RCV 60 and will put it in Kyosho's Corsair. I talked to Dr. Shaffer, who's corsair is on your website and he said it flys best with an APC 16x12. He's tried the Master Airscrew three blader 16x10 and he says it is not very good, in fact tends to stall the airplane on take off.. My experience with master airscrew is the same: They are by far less efficient to the APC. As for the efficiency discussion of APC's. I had that discussion again yesterday in a local hobby shop. The folks keep applying their direct drive experience. I guess one has to rethink completely with RCVs. Although they're turning the prop rather slowly, they put out quite some torque. So high pitch is essential. For example according to my program ("thrusthp"
0.937 hp is produced as follows:
16x10 APC @ 5850 rpm max speed: 55.40 mph! 15x12 APC @ 6000 rpm max speed: 68.18 mph! 15x14 APC @ 5698 rpm max speed: 75.53 mph!
But why am I lecturing theory, when I have a question: - What's the latest experience with props? Which work best? What about the Zinger props? How do they compare? - what's the diameter and thread size of the Prop axle on the RCV 60? need that to order the spinner.
Posts: 505
Joined: 4/11/2002 From: WimborneDorset, UNITED KINGDOM Status: offline
Hi Martin
Your theory was very interesting, so I am pleased you have included it on this forum.
In answer to your questions, we have numerous differing views on propellers for the SP series. The success of one prop over another really does depend on the specific application in which it is used. In light of this one of the best recommendations really is simply to try the prop. One of the latest inputs has come from Joe Wagner (a model aviation contributor and general engine guru). After testing our 60SP he found that 'Both the Graupner "Grey" and the Master Airscrew "Classic" 16-8 props spin at the same speed: just under 5300 rpm. But both of those props provide noticeably more static thrust than the APC does.' . Obviously we have never recommended any prop with a pitch less than 12, however perhaps on certain prop designs they do work well.
In answer to your second question, the propeller shaft size on the RCV60-SP is 5/16" UNF.
I hope this helps, if you have any more queries, please don't hesitate to contact me.
Hoooorayyyy, she flys!!! Kyosho Corsair with RCV 60.
I had a successful maiden flight yesterday. The engine performs beautifully. I installed a 3-blade-APC 13,4 X 13,5. Seems to be a good prop for the bird.
Some Details:
The Corsair weighs a little over 9 lbs. Thought at first that it might be way too heavy, but – no – it flies just fine. Just a bit on the fast side, but very stable. Good in stronger winds. It does like a warbird take off, though: full throttle, tail high and keep it down on the runway to build up speed… Landing the same: 2-wheelers on quite high speed, cause the Corsair is known to tip-stall… It is a warbird, after all
I installed Century Jet pneumatic retracts, 7 Hitec Servos (6 mini and one standard. MINIS: 2 ailerons, 2 elevator, throttle, retracts, STANDARD: rudder) along with two 5 cell 2100 Ah NiMh batteries. A Microsens SOLID 2 battery manager and model finder is installed as well as Microsens’ GLOW 4B on-board glow heater. The GLOW 4 B does not require an extra battery, which is very convenient. I moved the Elevator and rudder servos back underneath the canopy to make room for the bigger tank and the air bottle (retracts). With the batteries right in the nose aft of the firewall the C of G was spot on.
The rudder is linked by closed loop cables (self made rudder horns from 1,5 mm epoxy-fibre). Elevator is operated each with its own mini-servo, connected via carbon-pushrods.
I installed a Graupner 400 ml aerobatic tank and KAVAN light wheels, that I painted white. (applying a technique, that I am glad to share if anyone is intersted)
The firewall of the model has built in side and down thrust. Because of the great torque of the engine I increased the side thrust a slight bit (one washer) and left down thrust where it is, cause I expected the power to be somewhat on the weak side anyhow. Seems to be spot on. The washer also keeps the back plate of the engine away from the firewall. On my test stand it left a black, burned mark, so I thought heat might be a problem.
The engine has run about an hour on the test stand and in the model, just taxiing, before flight. Still gets quite hot. Hope that’ll be better after a while. Luckily the dummy radial did not melt…
And the sound is great. Strange, but great! Everyone at the field came to take a look when it was running. A lot of puzzled faces and more explanations… It was funny to see them sitting there, explaining the RCV-concept to each other… Like a bunch of guys trying to solve a riddle…
By the way: When the engine is warm, it starts very well with just one throw on the prop… So after engine-outs on the field (i.e. nose over) I just flip the glow switch on, kick the prop and taxi back off the field…
Posts: 505
Joined: 4/11/2002 From: WimborneDorset, UNITED KINGDOM Status: offline
Thanks for the feedback. I am very pleased to hear that it has all come together. The photos are also great. Would you mind if I used these, along with some of your experiences on our website (on the gallery section).
I look forward to hearing from you. Best regards Laurenne
as a matter of fact I had sent an E-mail to info@rcvengines.com along with some more pictures and about the same text. But it came back...
So yes, absolutely. Go ahead and put it on your website. If you need any more info or detail pictures (inside fuselage and so on) please let me know...
By the way I flew it again today. In 88 degrees F and calm condition. Scorching! Was a bit too much for the new engine, I suppose. It lost power after about 10 mins. I think it got too hot. Also the needle started to move. On my second take-off the engine stopped suddenly - before I was off the ground... I wanted to fire it up again but it wouldn't start. Then I noticed, that the needle was fully closed... Strange! I fired up again and as I opened the throttle, the needle slowly closed... so I bent the steel lip, that keeps the needle from moving, in a bit and it worked fine... But how long?
Also, after landing, I increase the needle setting a couple of klicks and let it run for a while, just above idle, to cool it down. Old radial engine practice... Cause if you stop it right after flight, it is very hot an fumes quite a bit... Great procedure on a warbird, though...
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