New prop for H9 40 Alpha
 

First post guys, so be gentle ;)

I have a 40 Alpha, RTF, so it came with the 0.45 Evolution engine. My instructor let me attempt my first landing yesterday, and I ended up breaking the prop, but thankfully nothing else. What the hey, any landing you walk away from.....

Anyways, I'm obviously looking for a new prop. I did some searches on this forum and see that there's lots of options out there, but a lot seem to recommend the 11x7 or 10x6 for this plane. From my understanding these numbers mean diameter x pitch. While the numbers aren't that different from each other I'm wondering what the difference between these two props would be. In other words what would be the difference in performance between an 11x7 or 10x6? It's probably not much, but I want to make sure I don't turn this plane into something I can't handle.

Also, I realize I need a new spinner, but it appears that some have had problems mounting two bladed props/spinners on this plane due to manufacturer differences and trouble with the back plate. I'm looking to keep this as simple as possible. So exactly what brand would you recommend to keep this easy, with as few modifications/parts as possible. I've also read the props sometimes need to be reamed to fit on the shaft? Is there another special tool that I need to use for this?

While I'm on the topic of plane of the Evolution engine, my instructor feels that with the current stops the plane is still running too rich. Looking at it, it doesn't look too hard to remove the stops, but I want to make sure I don't screw anything up. So is there a procedure outlined somewhere to do this the right way?

Thanks for all the help, as I get further along I'm sure I'll find all you guys here to be a valuable resource.

P.S. Sorry for adding another thread about the Alpha and Evo motor, but I found myself getting more confused after I did a few searches. So I wanted to make a consolidated thread for this topic to make sure I did the right thing.

RE: New prop for H9 40 Alpha
 

Just go to Tower Hobbies and buy any DuBro spinner thats the right size for your plane. 2" or 2.5"--whatever.

Props, 10x6 or 11x6 will work fine. The 11x6 will slow the engine down a bit, but might make the plane faster. Either one is fine. Don't sweat it, just buy a bunch of them and forget it. Buy 6 of the 10x6 and buy 6 of the 11x6 and try them out.

It's a trainer. It's a .45 engine. Just slap a prop on it and fly it. It's too early in the game for you to be stressing about prop sizes. Just concentrate on your flying.

If you think the motor is too rich, just take a pair of pliers and squeeze the limiter pin down inside the needle. That will allow you to adjust the engine any way you want.

Another thing you can do is just lift up the little clip that hits the limiter pin. Lift the clip up and turn the needle valve untill the pin is past the clip. Adjust from there.

RE: New prop for H9 40 Alpha
 

I also have a alpha 40. The prop that I found works best for me is a 10x8. It does slow the engine down but it gives a considerable bit more amount of pull in my opinion. I started with the 10x6 but found that the 10x8 gives me more room to work with. As for spinners I just bought an aluminum spinner and a washer. I have not had a single problem with the spinner since I bought it.

RE: New prop for H9 40 Alpha
 

I am guessing the spinner fit is because of the aft depth of the backplate, I found the same problem when trying to fit a plastic spinner on my trainer (it sat too deep and hit the nose). I found that the aluminum spinners (the ones with the single bolt in the center) have backplates that sit pretty flush with the prop hub and don't extend back behind it like the plastic ones do.
I use Great Planes 2-1/4" aluminum spinner on mine. (if you use an aluminum spinner make sure you also get a mounting adapter to fit on your motor shaft)
Prop reaming? there is a tool for that but I am willing to bet the standard size 10" or 11" props will fit your engine without any modifications. (most engines that size have a standard 1/4" shaft, not sure about the Evo?)

RE: New prop for H9 40 Alpha
 

i learned on a alpha trainer with the extra cra---on the engine, the guys above are right in all respects but you sound like you just began learning to land, just be ready for a little more speed with a 10x6 2 blade, the evo 3 blade is real slow compared to the two blade, you can do it but just be ready and good luck;)

the alpha is the same one i started with 2 years ago and the bi-plane is what i fly today, so hang in there you will love it!!!:D

RE: New prop for H9 40 Alpha
 

The 10 by 6 will be faster than the 3 blade, but not by too much. It should be fine.. Just idle in.. Better to have too much speed than not enough(stall)

RE: New prop for H9 40 Alpha
 

Change your prop hub and go from 10/6 to 11/7. Get rid of that extra weight on the crank for a 2 blade PROP;)

RE: New prop for H9 40 Alpha
 

Here is what I have done with this engine multiple times and it works. Minnflyer also has tons of experience with this engine, maybe he'll pop in on us :D

I'll address the second question first. There are actually 2 options you have here. You can completely remove the stops which is the best choice or reset the stops.

To reset the stops, loosen the set screw, retune the engine, center the stop on the new setting and retighten the set screw.

As far as prop choice, the problem with the spinner backplate is mainly the flywheel on the engine, that flywheel also is the prop hub. That flywheel gives the engine a very low, very smooth idle but does slow it down on spool up. There is a part that can be purchased that replaces the heavy flywheel with a "standard" prop hub but that will also remove some nose weight. On that plane, you should be fine but if you do remove the flywheel and replace it do not forget to rebalance the plane since you are going to remove about 2 or 3 ounces from the nose.

And lastly, the prop choice. With the flywheel off, an 11X5 or 11X6 APC (gray props) brand will be your best choices. Master Airscrew (Black props with white tips) will also work but they are not even close to the efficency of the APC brand. You could also use wood props but the APC will be better off considering they are heavier than the others and you will be removing nose weight if you replace the flywheel.

Now, you really do not have to replace the flywheel. If you do not then go with the 11X5 APC and for the spinner, the Dubro brand will work well. I beleive the backplate on that brand acutally sets back over the flywheel. It may be Great Planes, I just really cannot remember but as Missleman has suggesxted, the flywheel/prop hub is the reason. You may have to cut out the prop slots a bit but a dremel works well for this.

The 10X6 will also work in any brand, but I believe you'll be more pleasantly surprised with the 11 inch props

And I see Chad is quoting what he has heard versus experience again, pretty typical for him so be careful there

RE: New prop for H9 40 Alpha
 

To replace the spinner use #EVO040219 to replace the weighted prop driver then any spinner will work. Also I have found that the APC 10x7 is the best all around prop to use. Keep in mind that ths will increase top speed. To retune the engine file the stops off, this gives you full range of the needles. Loosen the set screw on the low speed needle and reset the the needle then tighten the set screw back so you can still use the lever for a fine setting. The plane plane top end will increase about 20mph. Dennis

RE: New prop for H9 40 Alpha
 

I have the same plane and motor, and I like using 10x6 MA props (Master Airscrew). I toyed with a few other 10" higher-pitched props and found that I liked the 10x6 the best. The 11" prop was too big for the field I fly on...it liked to cut grass. But now that I've put bigger wheels on it I may try an 11" again.

RE: New prop for H9 40 Alpha
 

the flywheel is not the hub, you can pull the flywheel off without the hub, taps right off;)