Help with prop selection, New Homie motor, 55"hull

[Rickracer]

Brand new Homie, no mods except gutted and piped stock muffler and big bore carb. I have been running a Prather 260 (SS). I have the following props at my disposal:

Octura X448, X452, X455, and X465, 1450, 1455, 1457, 1460, 2.1/3, X447 (3 blade), X460 (3 blade); Prather 260 (SS), and last but not least, a Prather 270. I have played with propshaft height and angle a bit but I can't seem to get much lift. The height and trim is now where it will cavitate if it turn it too aggressively, but hooks right back up coming out of the turn. The hull rides very wet, and the motor doesn't seem to be peaking. I've tried adjusting the needles, I can get it to what seems optimum, and poorer on both side of that, but it still doesn't sound right. Am I running too much prop? Will a header and chamber make an appreciable difference? Or do I just need more power for this amount of weight?

 

[Mike Saleeby]

Brand new Homie, no mods except gutted and piped stock muffler and big bore carb. I have been running a Prather 260 (SS). I have the following props at my disposal: Octura X448, X452, X455, and X465, 1450, 1455, 1457, 1460, 2.1/3, X447 (3 blade), X460 (3 blade); Prather 260 (SS), and last but not least, a Prather 270. I have played with propshaft height and angle a bit but I can't seem to get much lift. The height and trim is now where it will cavitate if it turn it too aggressively, but hooks right back up coming out of the turn. The hull rides very wet, and the motor doesn't seem to be peaking. I've tried adjusting the needles, I can get it to what seems optimum, and poorer on both side of that, but it still doesn't sound right. Am I running too much prop? Will a header and chamber make an appreciable difference? Or do I just need more power for this amount of weight?

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Lotta boat, not a lotta motor.

The best of the props you mention for your set up is the prather 270. About the best you are going to get with a hull that large is around the 30 mph mark. A tuned pipe will not make a lot of difference on a stock homelight in a big hull. Two things you need to be aware of in a big boat/ low horsepower set up. Make sure that the bottom of the hull is nice and flat--no hooks-- and make sure you are not carring a lot of weight in the bow. You don't have the power to lift the bow to free the boat up so let the hull do the work for you. Get the c/g back to around the rear 25%-30% mark, make sure that the bottom is straight because any kind of dips or hooks will act like trim tabs and force the bow down. Really need more info on the setup or even some pics to really help you out.

good luck

mike

 

[Rickracer]

Thanks Mike, I've got the motor at about 30% right now, it's 14.5" from transom to sparkplug. I am planning on some more power, but not gobs of it. Cleaning up the ports, bumping up the compression, and a pipe. The bottom is pretty straight, and the strakes are fairly sharp too. The major difference in this hull and my real boat is the lack of a pad, but I've gotten 80+ mph out of my Hydrostream Vector with a V-4 OMC on it, and took a 16' Glastron ski type hull from 42 mph to 70 mph with motor and bottom mods, so I understand what you mean about the bottom. My Glastron had a 3/8" hook that I had to fill, caused by a broken rear crossmember on the trailer. Should I consider moving the motor back some more?Maybe to 20%~25%? Or concentrate on making more power? B)

Edit: MAN that Prather 270 is a big prop, it's about an 1/4" bigger in diameter than the 260!!!!

 

[rhomodel]

Thanks Mike, I've got the motor at about 30% right now, it's 14.5" from transom to sparkplug. I am planning on some more power, but not gobs of it. Cleaning up the ports, bumping up the compression, and a pipe. The bottom is pretty straight, and the strakes are fairly sharp too. The major difference in this hull and my real boat is the lack of a pad, but I've gotten 80+ mph out of my Hydrostream Vector with a V-4 OMC on it, and took a 16' Glastron ski type hull from 42 mph to 70 mph with motor and bottom mods, so I understand what you mean about the bottom. My Glastron had a 3/8" hook that I had to fill, caused by a broken rear crossmember on the trailer. Should I consider moving the motor back some more?Maybe to 20%~25%? Or concentrate on making more power?  B)
Edit: MAN that Prather 270 is a big prop, it's about an 1/4" bigger in diameter than the 260!!!!

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The cg is not where you put the engine, altough the engine has the largest effect. I think you should (may be you do but that is not clear to me) measure the cg of the whole boat RTR. With a big boat and a small engine try to get it at about 25 %. Prather 260 is really little prop for a homie, not a lot of revs but a lot of torque. Many guys run a prather 275 and a 280 on smaller hulls like 45 inch or so.

There are more mods to be done to a homie to bring it to life. Take a look at http://testfly.0catch.com/homelite/homelitemain.html one thing that is not mentioned is stuffing the case. What is done very often is that the backplate of teh case is thickened with a plate to reduce case volume.

Julius

 

[Mike G]

I agree with Julius, all your props are way too small, 275-280 minimum!

Remember Mike S said the "270 was best of the ones you mentioned" I'm sure he would agree even bigger would be better.

3/16" props are nitro sized. Stock homelite has plenty of torque to turn a big prop.

 

[Rickracer]

Anybody got any props to swap? All of the above are now trading material, I guess I need some bigger props. B)

 

[Rickracer]

Well, I tried the 270 today after we came back from the WinterNats, and man what a difference. I bet the boat picked up 5mph, and it was actually developing some lift., and you could see the hull torque roll when the throttle was stabbed. I like that When I start making a bit more power, it should be nearly perfect. Guess I need to pick up a couple more props too. B)

 

[NAMBA860]

Anybody got any props to swap? All of the above are now trading material, I guess I need some bigger props.  B)

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i have several big prather props i will go home and ck. the size tonight and i have a big prop shop 3 blade also i would like the octura x 448/452/455/465 2 blades and the x447/460 3 blades. i will email you the sizes tonight.

 

[Rickracer]

Kewl! I'd like a 275 and a 280 if you have them, and I might like to try the big 3 blade too. B)

 

[ernest2]

what kind of homie do you have? is it watercooled or a trimmer engine?

 

[Keebibear]

I have a brass 280 or a 275 Ide trade for your 1450.Let me know at [email protected]

 

[Rickracer]

Thanks, I'd like both please, anything else I have that you want? Don't make me have to choose . You can email me at [email protected] for shipping info.

 

[Keebibear]

Shipping info sent.

 

[Rickracer]

Your props go out tomorrow. Thanks,

 

[NAMBA860]

Your props go out tomorrow. Thanks, 

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I HAVE AN OCTURA 1465,2160 PRATHER 270STAINLESS,265 STAINLESS,275 BRONZE AND A PROP SHOP7016 3 BLADE BRONZE IF YOUR INTERESTED IN A TRADE

 

[Rickracer]

Thanks 4-EST PERFORMANCE, I would be interested in the 270 stainless, I don't know about any of the others. Right now, I've got a 270 on the boat, and it made a big difference over the 260. I've got a 275 and a 280 on the way. My plans include rigging a AeroMarine 43" Sprintcat with a K&B 11cc nitro motor to begin with, then a modded Zen 230 or stock 260 when I can afford it. I already have the K&B, it just needs a piston, liner, rod and wristpin. That motor was on my 55" Dumas when I got it, but blew up immediately. If any of the props you mentioned would work for the cat combos mentioned, I'd be a player. B)

P.S. I'd also be interested in a good 1/4 scale servo for the cat for partial trade too, if you've got one.

 

[NAMBA860]

Thanks 4-EST PERFORMANCE, I would be interested in the 270 stainless, I don't know about any of the others. Right now, I've got a 270 on the boat, and it made a big difference over the 260. I've got a 275 and a 280 on the way. My plans include rigging a AeroMarine 43" Sprintcat with a K&B 11cc nitro motor to begin with, then a modded Zen 230 or stock 260 when I can afford it. I already have the K&B, it just needs a piston, liner, rod and wristpin. That motor was on my 55" Dumas when I got it, but blew up immediately. If any of the props you mentioned would work for the cat combos mentioned, I'd be a player.  B)
P.S. I'd also be interested in a good 1/4 scale servo for the cat for partial trade too, if you've got one.

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I WOULD TRADE YOU THE 270 STAINLEES AND THE PROP SHOP 3 BLADE FOR YOUR X460 3 BLADE AND THE X465 2 BLADE

 

[Rickracer]

Sounds OK to me. Can you tell me more about the PropShop 3 Blade? Where would it fall in relation to the 275 or 280? Or would that be a blade for the Sprintcat? B)

 

[Keebibear]

270 is smaller with less pitch than a 275 and 280.

 

[Rickracer]

No, I meant how would the Propshop 3 blade compare to the 275 or 280? And while I'm at it, if a guy were to have a bronze 275 and a stainless 275 which would be better to mod? B)