Noob here !

The plane is a Kadet Senior ARF (a.k.a. the flying whale or blimp with wings [8D] )

Engine is a 2-cycle Tower .75.

It's my 1st plane, will use as a trainer. I want a prop that'll be the "best" overall for initial use ( 1/2 throttle buddy-boxed training flights) and eventual post-noobie full-on throttle mild aerobatics.

Since I have a digital tach, what RPM would I be looking for at wide open throttle as I assume the prop length and pitch will limit the oveall achievable RPM's ? Is that how you guys choose a prop ? Just experiment with various props and go for a certain max RPM @ WOT with the eventual prop choice dictated by the overall power of the engine and it's ability to spin the prop at the target RPM ?

I also realize that all things being equal I should go fo a shorter prop with more pitch in the event of nose-overs as I'm less likely to whack the prop ?

Thanks.

Joe

I don't have a specific prop recommendation, but I can tell you that you will not nose-over this plane.

I fly my Kadet with a Magnum .91 and a 14x8 APC prop. Do yourself a favor and ditch the wire gear and get a set of nice aluminum or Dubro main gear and a Sullivan or other (longer) nose-gear. The stock foam wheels will be fine while you are learning and beyond.

Your engine manual will have a range of props that are best suited for that engine. Honestly, as long as it does not over-rev or over-heat your engine it will be fine. Yes it's big and slow, but it's a fantastic trainer and a darn nice airplane. You can see it for miles and it lands like a feather...what more could you ask for in a trainer?

That engine is more than plenty of power....like too much power for that airframe. You could rip the wings off!!! But seriously...watch the throttle with that thing or your Kadet will land itself minus the firewall. (Consider adding triangle-stock to the firewall...there's plenty of room).

Props are very important, probably as important as tuning, but for a trainer that will be used as a trainer, maximum power is not really needed. Some props will deliver power more quickly, some will be better at vertical etc.... Just get a prop in the range that the MFG recommends and go fly!

Welcome to the end of 'free-time' and 'disposable-income' as you know them.

actually when training you'll want a larger overal prop length with less pitch to reduce overall speed. 12x6 will be fine for what your doing.

your idea on prop selection is pretty close. base it on wot and target RPM range. The actual prop choice once you find the RPM range you want is based on what you want to do.

speed you want a small diameter prop with a high pitch. with this your climbing rate will suffer and acceleration will suffer but top speed will increase.
with a larger diameter prop with a smaller pitch will giver better acceleration and better vertical climb but will go slower.
a sport prop would be somewhere in the middle.

this is kinda of allot of motor for a trainer so use the throttle wisely. I wouldn't choose a prop based on nosing the plane over. if it's going to go over it doesn't really matter how long the prop is, it's going to break. If your props are hitting the ground is because their to big because the motor is too big. the plane was meant for a 40. recommend a 46-52 running a 10 inch prop. since your going with a 75 you'll either have to rework the landing gear or go to 3 blade props

Well, I'm no pro yet but I'll try to explain it the best I can. The flatter the pitch, the better pull type performance you will get. It will spool up faster & get you off the ground easier. The higher the pitch, the faster the plane will fly at high speed. For instance, the OS .46FXI flys very well with an 11X5 or 11X6. It has plenty good pulling power as well as pretty good top end speed. A smaller diameter prop with a high pitch will make for high speed, while a larger diameter prop with a lower pitch will give better low end performance while still being plenty fast enough for learning & most sport flying. This should be enough to get you started & the others with more experience will chime in & correct any mistakes in my attempt at explaining this to you.


http://www2.towerhobbies.com/cgi-bin...?&I=LXUR78&P=0

This is the engine you bought right? According to Tower's recommendation a 12X6 or a 13X6 is your prop. I think it will fly well with this prop & not get so fast at top speed that it scares you. I have a TS .56 swinging a 12X6 & it feels real good, lots of torque, & plenty fast enough if I want it to be. It's on a much lighter, faster type airframe, but it will go straight up no problem. Since this is a Trainer that you are gonna learn on buy a few props of each of those sizes, you're gonna need them anyway. It's plenty big enough to swing the 13X6, ground clearance shouldn't be a problem. The only time I broke props on my Trainer was on the ground. Not so much from bad landings although there were a few of those too, but mostly from the the wind tipping a wing over after landing while taxiing back to the pits. Tower likes to recommend Top Flite wooden props, but the general concensus around here is that a nylon prop is safer while in training. Like an APC or a Master Airscrew. It's easy to scuff a wodden prop & as a student not notice a hairline crack in it. There was a post about this a few months back which I found to be very true as I allready had a bag of Top Flite 10X8's that came with my Tower Trainer. Every time the wing tipped I was putting on a new prop. Good luck in your training & welcome to the great Hobby/Addiction.

But he did stay at a Holiday Inn Express last night. [X(]

One thing to remember is a Telemaster has a airfoiled tail section so that translates to the tail lifting very quickly on takeoff and really really slow landings. So you need a less pitch more diameter prop. We have a guy where I fly at with one of these. He first had a 6 pitch prop and in a head wind it was nearly impossible to get it to land as it simply just did not want to stop flying. You literally had to kill the engine.

We finally got him to change to a 5 pitch prop and it really did make all the difference in the world. So as was already mentioned, keep the diameter up and the pitch low

If the engine is new then a 12X5 APC prop. If the engine is already broken in then a 13X5 APC prop would be just about right for that airframe. Telemasters do not like speed. They can take it but they need tons of trim when flown fast. They also make great tow planes when done being used as a trainer and if you convert it to a taildragger then you have a whole new plane

Hey Bill, where is anyone here talking about a Telemaster? Hehe, think you ave the wrong plane or wrong thread in mind buddy. A bit OT, but I've had the pleasure to fly my buddies Telemaster a few times; man, I could practically take a nap while it flew around! Its just such a relaxing and fun plane to fly, especially since that one had opening bomb doors for candy drops.

I can't suggest a size/pitch, HOWEVER this may help.

A Master Airscrew prop (the black one) is not as efficient as an APC prop. The equivalent is roughly 1 size larger in pitch for the MAS over the APC for about the same performance. If you watch a MAS prop from the side with the engine is running, you will see it "flexes" noticeably more than an APC.

The advantages to a MAS prop is that they are more tolerant of prop strikes than an APC and if you need to slow the plane down for landing these work great (I had to put a MAS on my SIG Rascal in order to get it to slow down enough to land).

The down side to the MAS props is that they are noiser than an APC (about 3 - 5 db). The noise thing may or may not be an issue where you fly.

Yep, I screwed that one up royally....Sorry folks. Wrong plane mentioned but the recommendatiuon for the prop of that engine still goes

In seven replys, only one of you mentioned what I feel the proper place to find information on proping this engine! "Read the owner's manual" and go with a prop in the middle of the recommended range! This engine IS bigger then needed for this plane. Wise throttle management will allow it's use, but don't forget this fact. The Kadet is a great trainer. As far as mild acrobatics are concerned, this plane is really limited to basic aerobatics; but, you'll have lots of fun dispite!

That's just wrong!![sm=punching.gif]

For some reason I thought we were talking about the Senior Telemonster too.

Hi!
First your .75 engine is a little too powerful for that airplane, a .60 is more suitable .
But I don't think you will change just because I say so. So get a 13x5 or a 14x4W APC prop.

Regards!
Jan K
Sweden