khoat6

im building a 1/12 house of balsa p51 and am powering it with a ap hornet 09 engine. the engine is kinda wierd because of its backside muffler. but im having trouble installing the prop (airscrew 7x4) and the spinner (dubro 1 1/2"). the kit has a ply spinner ring and suggests that i sand the front end of the fuse to leave a 1/32" gap between it and the spinner backplate. but when i try to test fit the prop and spinner, there are only about 2 threads left on the crank shaft for the prop nut. but the prop nut supplied with the ap hornet engine is a combo of a spinner and nut, and thers no room to put it on. do i use a different nut? or am i supposed to make more room on the crankshaft? (there is a thrust plate at the begining of the crankshaft...so i leave it there or take it off?) sorry but im a noob and need lots of help building this kit...i have pictures but dont know how to post...i can email to show u guys...maybe youll understand my pictures better....any help would be great please!!!

khoat6

i just found out how to upload pics....sory im new to rcuniverse...i will post them asap to give u guys a better understanding of my problems...

khoat6

here they are....please help!

khoat6

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tsands

My Feedback: (3)

no experience with engines that small. just a ? are you using the right prop? it may be too thick. You NEED that washer on there so removing that is not an option.

Madd_Maxx

khoat6:

If you are going to use that prop nut I wouldn't even bother putting the spinner on that motor. I have been using dubro prop nuts (like the one you are using) for the last year or so and never use a plastic spinner anymore. Just leave the platic spinner back plate off the crankshaft and see if you have enough threads to use the prop washer (a must) and the aluminum prop nut.....there should be enough threads showing. If you still have problems getting the prop-prop washer - prop nut on the shaft you may have to look into a thinner hub prop. Some props are a bit thiner where they mount. Wooden props tend to be a bit thinner then say an APC or MA prop....but I'm using .40 and up sized motors so you may find things a bit different with the smaller motor you are using.

Madd_Maxx

Pilot Chad

My Feedback: (4)

Mad Maxx summed it up, just use that prop nut. It will also look more scale like that.

RCKen

My Feedback: (9)

Chad,
Sorry to have to correct you, but there is no way that a spinner nut is going to look scale on a P-51. All P-51's had a spinner on them, see the attached picture. Since you brought it up, to make this plane look scale he's going to have to put a spinner on it.

khoat6,
To get it to fit with a spinner, the easiest solution for you is to sand back the front of the fuselage. Since you motor is already mounted in place you need to sand the front of the fuselage off until the spinner ring, spinner backplate, prop, and spinner will fit properly. Please see the second picture to see what I am talking about.

Hope this helps

Ken

2slow2matter

My Feedback: (1)

Then, you are going to have to come up with a regular nut that will fit on that shaft. You might call the man. of the engine to see if a regular prop nut is available. Or, if you really want it to look nice, then you could get an aluminum spinner. The adapter you'd have to get for it will have a prop nut built in. Hope this helps some. The safety nuts are nice, and make switching props a breeze. However, as RCKen pointed out, it would be in no way scale for the P51.

Pilot Chad

My Feedback: (4)

Stupid things i have done today...
#1 Say a P-51 did not have a spinner...

khoat6

thanks guys for all the input...
rcken, i am goin to sand down the front end of the fuse (the directions say to), but that will only change the spacing of the ply spinner ring....the spinner back plate cant go back any further, so i think im going to have to get a thinner spinner and a regular nut to hold on to the spinner. but will the spinner need a washer before the nut? btw, the spinner im using is an airscrew 7x4 size which was suggested by the AP engine manual.
also, the prop didnt fit the crankshaft, but i dont have a reamer....would a drill be ok? and should the prop screw onto the shaft, or does the prop opening need to be big enough for it to slide on the shaft freely? thanks for helpin out the noob...

khoat6

if you guys had a picture of your setup with a spinner, thatd be great visual aid for me

bubbagates

My Feedback: (32)

khoat6,

I really do not have experience with that particular engine but I can say these things. Airscrew props are usually very thick around the hub so that may be some of the problem. APC props are thinner. I do mention this as that is how it is on the larger (40 size and up) engines.I could be completely off base with this engine

Starting from the engine out. spinner backplate, then the prop, then the prop washer, then the prop nut, then the spinner. The only options I see so far is no spinner backplate and spinner or a thinner prop, but a mustang just screams for a spinner.

The pics you have show a dubro prop nut, while they are excellent prop nuts they are not normally used with a spinner. I am guilty of doing it though because I lost the standard prop nut and the dubro is all I had but this was on a OS46AX so I could use a larger spinner setup that had the room for the dubro prop nut do to the longer prop shaft bolt.

I do not remember you mentioning if you had the original prop nut or not that came with the engine but that and a prop with a thinner hub, like an APC or Zinger wood prop would help. If you look at the threads on the dubro prop nut you have now you will notice that the threads are actually inset about 1/16th inch to 1/8 inch into the hole. So that means you are losing even more space.

From your description I would do 2 things, get a prop that is thinner at the hub and use the original prop nut. It will be hidden by the spinner anyway.

As far as how tight the prop is on the shaft. You can use a drill. You must not make it oversize and then can be absolutely no play once the prop is on the shaft. If you have to screw it on the shaft that is OK as long as it is not really tight. Almost all of my APC props need to be screwed onto the shaft and once they get past the threads, I can usually push them on the rest of the way with my hand. Just being able to push it on is OK also but as I mentioned there can be no play once it's on the shaft. You check that by grabbing the prop once it's all the way on and see if it wiggles. Do not have the prop tightened down to check this as it will give you a false reading. A loose fitting prop will cause all sorts of problems from severe vibrations to a destroyed engine to the prop throwing a blade and a few others.

BTW...when we talk about the prop hub that is the center of the prop where the hole is

khoat6

thanks alot bill...
the prop nut (dubro) in the picture was supplied with the engine...
will i need a special prop washer or can i just use any kind of washer? where can i get differnt prop washer and nuts to accomodate my setup....do i have to go to the hobby shop? or can i go to home depot or lowe's or etc...?

bruce88123

Be sure you do not modify any prop hub to make it thinner as this will make it unsafe. I usually work out my prop/spinner combinations off of the plane and then install the combination(assy) into the plane.I find it easier to get proper clearances that way.

bubbagates

My Feedback: (32)

The best way is to have the prop washer and the prop nut that came with the engine. Scratch that, I just looked up the engine and it comes with what you already have so everyone knows, here is a pic of it.

I would do the LHS first. It will be more expensive but it will be a better match.

I'm a little short on time or I would do it for you, but a little research may yield someone that has the correct prop nut/washer combo

Here is where I found the picture. It shows the shaft size. Now that I have looked it appears from re-reading your posts that you did do some homework. Cool stuff. I did a very quick look at the recommended lists of items for this engine and it seems you are dead on.

http://www.hobbypeople.net/gallery/211300.asp (there are other places but I'm a little short on time)

I'll be back later to check this out and if no one has posted about finding or not finding a prop nut for you I'll dig a little deeper.

khoat6

thanks again bill, ill try to do some more research and hopefully can find the right combo soon...ill let u guys know how it works out...and show u the pics...thanks again for all the help guys!

2slow2matter

My Feedback: (1)

I wouldn't recommend anything from the hardware store. The metal in those nuts and washers seems to be soft, as compared to what comes on a glow engine. You need a prop washer. The prop washer is designed to distribute the force of the nut evenly throughout the hub, so as not to weaken the hub, or have your nut/washer assembly burn into the hub. I'd find out the size of the shaft and the threads (easy to do), and then order a nut and washer from tower or similar (or LHS). If all else fails, call the manufacturer.

bubbagates

My Feedback: (32)

I just went through 10 pages of a google search and have had no luck on finding the shaft thread and size other than that the shaft is 5mm...

2slow2matter

My Feedback: (1)

I just looked through hobbypeoples pages. They seem to have everything made for the hornet. The only prop nut is the spinner nut. You may not have a choice afterall. New engine, or non-scale, prop nut. Sorry...

bubbagates

My Feedback: (32)

2slow,

Yea I saw that earlier today when I first looked. I'm wondering if he finds out the thread size would it be possible to see if maybe Norvell or someone else that makes an engine that is similiar may have something that will work.

Just a thought

2slow2matter

My Feedback: (1)

Yea. Shaft size is 5 mm, but it doesn't tell what slope the threads are.

khoat6

well i could change to a norvel .074, but the thing is ive already epoxied in the firewall and the engine mount.... and im quite sure another engine wont fit because i had to custom fit those in due to the ap hornet's rear muffler setup... i think my only solution is to get a thinner prop and prop nut... ill try the hobby shop tomrow and see if i can find any subs... ill let u kno how it all wrks out.. thanks!