No, never saw that gage. wouldn't be cutting it in half, from 26" to 22", doing so, how will this effect the prop performance? pitch?

I think to swing a 4-blade prop with scale diameter (20" diameter prop on a 66" span plane), it is more efficient to use a gear-reduced engine such as RCV, or electric motor. I don't see too many RCV engines around, maybe they never catch on? However, electric is coming like a storm and we're just seeing the tip of the iceburg.

Now some people have come out with "warbird sound speakers" to install to your planes to make electric motors sound like WWII engines. I am not sure how well that would work out logistically, or how much more battery power is required to make impactful sounds. But I will tell you one thing: no glow or gas RC motor sounds like a Merlin quite yet.

Richard L,
I would rather run a slightly smaller than scale 4 blade prop on my Mustang than an ugly not scale at all 2 blade prop. I am using 3 blade props on my Ziroli B-25J, because I have put too much scale effort into her to shame her with 2 blade props.

Kilroy52,
Keep the 4 blade info coming if you try anything else.

"Keep 'Em Flying!"
Flak

Hey it's your plane. You can put whatever prop you want on it. One thing for certain, a Mustang with scale diameter 4-blade static prop sitting on the ground will look much better than one with a dinky 4-blade prop.

Hay Richard, I beg to differ, The Four Blades I am using don't look dinky In fact thay look just right. I have not ever had one person say that the prop looks to small, insted thay say, Boy thats is a lot of prop. I don't have the set up to put a picture in this forum. I think if you seen them you just might agree.(At least a little) As a matter of fact I think that 20" prop would look to big.
And not only that, but when people are standing there and want to see the plane with the four blade prop fly, and you have to say, oh whell that is just a toy prop for you to look at, thay turn around and walk away. And guess whos planes thay come over to see fly. A little off scale thay may be, but thay are all standing around by my pit. I have even changed the mind of a few of the old hard core scale dudes in to thinking, Hmmmmm he just might have something there.
Don.......

Kilry 52,
I believe Richard L may be one of those, how did you say it, (looking back at your last reply) Oh, here it is, "Old hard core scale dudes"...LOL. I'm only kidding Richard L, so keep your scale exhaust ports open. I believe the intent of this thread was FLYING with a 4 blade prop. Can you post some photos of your ponies with their 4 blade props. A video would be even more convincing for the scoffers! Good luck.

"Keep 'Em Flying!"
Flak

Well, once the engine is running, I only care about seeing a nice big yellow prop arc:



I'm not going to stare at the spinning prop to determine how many blades it has.

Even with the plane on the ground, the big prop arc looks decent even though the prop has only two blades:

* [link=http://www.whitetyphoon.com/rc/h9_corsair/movies/SlowIdle.wmv]Corsair Idling[/link]

I have to admit 4-blade props do look better when they are sitting still, provided that they are not gray APC's.

Richard L,
The yellow prop tip at each end of the prop in the prop arc is a dead give away to it being a 2 blade prop on a 4 blade aircraft. No counting required. I just wanted to point that out.

"Keep 'Em Flying!"
(No matter how many blades)
Flak

I would have to side with Richard L

I have come to believe that there is "affirmitive action" scale and scale itself. Both will work in there respective circles. I have been in both..

I am about to get a CMP 54" P-51D. I'll fly it with a 2 blade. Although I could build a carbon scale blade for the P-51, the engine needed to turn the scale blade would probably rotate my airframe easier than my prop.

But I have a BF 109G that will fly with my carbon scale size three blade with correct blade shape . The model would fly with an OS 108 two blade, but I have purchased a Moki 2.10 for my scale blades. Should work. ??

Steve

Hi Kilro52

How about a few picks of your model with it flying blades??

I would love to put up some picks. But" I do not have the technology.... However I can tell you where to go to look at some...... Go to www.alvinrc.com Then over to the right, Click on
Mobile Area R/C Forum..... Then Click on Forums Main Page .....Then Click on RC Scale Aircraft
Then Scroll down and Click on Slings Picture Corner.......Check out the picks....When you see Mustangs with (YOU KNOW WHAT) Thats me.... Also when you click on a picture, ImageShack will open up with that pick.You can then click on it to enlarge it.....Then X out to return to the Forum..........While you are there, check the rest of our clubs forum. I think you will enjoy it....

Don

Scalecraft,
I believe it's unfortunate we have to choose sides. However, flying with a 4 blade prop without a reduction drive is possible as has been stated by Kilroy52. There are too many EXPERTS in any hobby who claim to know it all, but are afraid to face new challenges and make change in what is all ready ingrained in their fortitude. I was scared to death of computer radios when they first appeared. Now I have one and get tickled when I learn a new feature that helps my airplane fly better, (I still have a few non-computer radios I use regularly). How about trying Kilroy52's method and see what happens? I'm going to try it and see what I can determine for my own benefit. One small step for a modeler, One Giant Leap for Model Aviation!

"Keep 'Em Flying!"
Flak

Guys, you need to read the posts a bit closer... NOBODY SAID FLYING WITH A FOUR BLADE PROP "COULDNT" BE DONE! What has been stated, and is a FACT, is that a four blade prop of "scale" size for a Mustang, Corsair, etc, would be too big for most R/C engines to pull without damaging the engine. Flak, you and Killroy are talking about running four blade props that are 4 to 5 inches smaller in diameter than they would be if they were actual scale size for the planes you are putting them on. Of course they will work when they are that much smaller, and I will agree they look 100 times better on a warbird. What these guys are trying to tell you is that in order to be of scale size in proportion to the aircraft, the prop would be too much for the engine, without a reduction drive of some sort (like the Byron units of a few years back). No one is trying to tell you that a four blade prop cant be used at all.

Kilroy

Your model looks good in the pics. However, if the pics are of the prop not in flight, and static pics of the model on the ground as shown, why not display it with a scale static prop.

I may have missed the flying pic??

Still looks good on the ground

Steve

Steve,
Because it is all about the OOOOOOOs and Ahhhhhhhhhhs factor The prop is not as large as it should be BUT" I have found that nobudy notices, Except for the occasional, REAL SCALE GUY.The bigest thing that impress people is the fact that thay see this four blade prop on the plane, and I start up the engine and fly with it. I am telling you people just can't beleve it. Thay ask me, WHY don't those other planes have that. And when you are flying and you bring it in for a low pass nice and slow, so the folks can get a good look, and hear it as you power out, THAY LOVE IT. Thay will give me a round of applause!!!!!! HAY I ain't the doing 3D stuff here, I just made a low and slow pass.. I hope nowone at my club gets a four blade, because my planes get all the attention. When the people walk past all thost big jumbo Mustangs with there two blade props to come down to my end of the pit to look at my little 40 and 60 size Mustangs, it's GREAT!!!! when this happends to you, you will NEVER put A two blade prop back on your plane. And a static display prop, it turns people off, thay think tha plane should fly with the prop it has on it.....At least this is what thay tell me..
Don

Lowlevlflyer,
Well!!!! at least you understand what I am trying to say[sm=thumbup.gif][sm=thumbup.gif] NO, it is not 100% scale. But SO WHAT. the tail wheel is not scale,the retracts have covers, but thay are not scale, the cock pit has a decal on the dash and 1/2 of a guy in it, thats not scale. And I don't intend to enter it into a scale contest. I will however enter it into a, Well it kind of sort of looks like a Mustang is supposed to look contest..

I never said I was trying to BE 100% SCALE. What the guys are saying is most likely true, if you want to be 100% scale, it can't be done. But realy, how meny 100% scale planes do you see at the average flying feild. So the guys with the BIG planes are out of luck, thay will have to settel with using a static prop. "YUCK"

Another thing I did, Now this is going to make the all scale guys say WHAT!!!!!!!

The 40 size Duchess Arlene (Tuskegee Plane) is some what smaller then the 60 size Marie, and being gray top and bottom is hard to see at times. I almost lost it a couple of times beause I could not tell the top from the bottom .Soooooooo (Hear it comes) I put D-Day stripes on the top of the wing[X(] OK OK OK, I know, the Tuskegee Airmen did not have D-Day stripes on there planes. That is better then me CRASHING IT. And rember we are not talking 100% scale here. And a couple of the "SCALE DUDES" at my feild didn't know this untill I told them.

Don

If you like the four-blade prop... go to town. This hobby is all about doing what ever makes you happy. What makes me happy is running a two-blade prop that gives me the best performance from my engine. I don't drag my models to the field to set them next to others on the apron and stare at props, I go to fly.

I have a 60 size Top-Flite Sea Fury with a Saito 1.00 and a 15x6 prop. If you and I were to fly together and we did a level pass down the field, the Fury would be traveling roughly 50% faster then the Mustang. If you drop to 3" of pitch it's going to be closer to double the speed. That doesn't sound like fun to me. When I fly with other warbirds I don't want be constantly cutting corners in the pattern just to stay with them; only to have them blow my doors off on the low pass... I want to be with them for the whole loop.

Speaking of reduction drives, I bought this Byron Mustang 3 weeks ago at a swap meet. It has a 24" inch prop with 15" of pitch.

Scott.

Hi Scot,
Performance is all in how you look at it. If I put on my 15x6 two blade, it is faster, I have a Saito 100 in it, I am sure it would give your Sea Fury a run for it's money. The performance with the four blade is just as good, slower yes, but not by 50%, it flys faster then what thay call scale speed....I don't drag my planes to the feild to set next to the others to look at props eather, as a matter of fact, most of all the scale planes are about 200 ft on the north end of our pit area away from me. I fly this plane a lot, it doesen't just set there.I only fly with a couple other warbirds and can keep up with them just fine, beleve me, it's not a slow poke. I think what it is, is that all the scale guys at my feild have been telling eveone for so long, that you can't fly with a four blade prop, that when people see it, thay are surprised... If I ever come to San Diego to fly with you, I will bring my two blade

That Byron is COOL!!!!! Now thats what I call scale[sm=thumbup.gif]

Don

A Merlin engine has maximum revs of less than 3000 rpm, so a large prop with lots of pitch and blade area is required in a full size Mustang.

A model engine (even a big one in a 40 size model like a YS110) revs at over 9000 rpm, so the prop is smaller.

There are lots of scale effects like this, mainly because if a linear dimension, say , doubles, the weight increases 8 fold.

-David C.

Scott, now THAT is a mustang!! Very sweet indeed!

Actually going from 6" to 4" is only a 33% decrease in your theoretical max speed. Going from 4" to 6" is a 50% increase. If you dropped from 4" to 3" it would be a 25% reduction from where you are now with an expected max speed of ~28 MPH at 10k RPM. This doesn't count for inefficiencies and the general rule that nothing ever works as well as we plan... . Also, this assumes level flight, not speed during or after a dive.

With a 3" pitch prop and a 10 MPH headwind, you might be able to outrun your airplane.

If you want to predict the max speed for a pitch use this equation:

( RPM * 60 * pitch in inches)/63360=MPH.

Someone feel free to correct me if I'm wrong; this has happened many times before.

As for the Byron, I think it's cool too... unfortunately, I cannot take any credit for it. It was built by a guy in our club who sold it to me at a recent swap meet.

Have fun,
Scott.

Ahhhhhh yes, and if you have double vision, you are still only looking at one thing

I have nothing against muti blade props. In fact, I am building an all composite 80" BF109G that will have my scale size and shape carbon blades. Variable pitch (manual adj)

I have a home made gear down system for my 108. If that fails I have purchased a Moki 210, which should handle the 20" arc blade.


All that matters if it it works for you and your having fun.

Steve

OK Scott,
I am not going to get into the numbers with you.You sound like you know more about it then I do[sm=thumbup.gif] I am just passing along some info on what has been working for me, and how folks have reacted to my planes..Right or wrong, thay fly great for me, and thay look good.

Don (Kilroy)

How do you work this (in reply to) thing??????? Some times I am replying to the wrong person. Bear with me, I am new to this Forum talking, and don't know how to work everything. Thanks.........