New project 41 inch mono

[Old School]

I am considering a new project based on a 41 inch mono hull from Hobbyking. The unit comes fitted with 4 mm drive and a 4074 2200kv motor. The recommended ESC is a 180 amp model. I can utilise the 4mm drive on a current 70 cm mono hull project and no doubt my son would find a use for the 4074 motor.

Now my intention is to gut the motor and driveshaft/stinger, reinforce the hull interior and fit a 5692 1340 kv motor running on 6s with a 220/240 amp ESC and 450 prop. Obviously, the drive will need upgrading. Would it be overkill to fit a 1/4" drive or would a 3/16" drive be suitable please? I would retain the existing rudder setup.

[martin]

Im assuming that you are talking about the 41" Osprey from HK, if so the boat comes with a 3/16" (.187 ) drive. HK specs are wrong stating 4mm drive ( HK famous for getting specs wrong ). 3/16" flex will be fine on a 56 series motor.

[Old School]

Many thanks. I am surprised that they would get that wrong. The motor still looks like a Leopard Hobby item.

[ray schrauwen]

I ran a 40" mono on 6s2p, an SSS 5684-1200kv motor, sf240 and big props like 55mm range. Fun boat.

Sold it because can't handle large heavy boats anymore.

Took in Qmono at the FE Nats in Michigan a few years back.

[Old School]

Many thanks. When you state 6s2p, I assume that this is two 6s packs running in parallel to give more amperage draw potential and possibly increased runtime. I am new to this lipo game.

[Fluid]

An option for power is a smaller format motor. Several years ago a couple club members build a couple 41” DeltaForce monos powered by Neu 1527/1Y motor’s on 6S. Performance was outstanding in these lightweight hulls, which were not dissimilar to the OP’s hull. A lighter weight option which has proven performance.

Running 2P means twice the run time and the potential to safely draw more amps. It is common for larger hulls, and smaller racing boats too.


.

[Old School]

An option for power is a smaller format motor. Several years ago a couple club members build a couple 41” DeltaForce monos powered by Neu 1527/1Y motor’s on 6S. Performance was outstanding in these lightweight hulls, which were not dissimilar to the OP’s hull. A lighter weight option which has proven performance.

Running 2P means twice the run time and the potential to safely draw more amps. It is common for larger hulls, and smaller racing boats too.


.

Would a more suitable combination be a 4092 1390kv running 6s and around a 47mm prop, please. I would most likely replace the stock motor mount if choosing the 40 series motor. I am not after a speed record, only something that gets up and moves. The 56XX series are heavy anchors.

Not necessarily a Leopard Hobby motor but just considering the amperage draw - LBP4092/4D 110A 26V

[CraigP]

That's a good voltage, kv and prop combo to start. I bet you could end up turning a bit more prop, but certainly wouldn't start there. A sport boat should work with a 180a ESC. Nothing wrong with a Leopard motor for a sport boater. Keep the rpm's no higher than 35,000, should be very reliable! I have a 20" Mono running 6s with a 3674 1400kv motor and it just flies, running a M445 prop. Some put 40mm motors into these hulls, but I got to tell you, I'm impressed with the 36mm!

[Bp9145]

you can certainly use a 4092 1390KV motor but still keep the 220A or 240A esc. . .will be easier on gear and you can use bigger props. .50mm and up. Just remember if you want to get that longer run time you desire a 2 blade prop will give you a longer run time than a 3 blade prop just in case you were also thinking of a 3 blade. Although, a 3 blade prop has it's advantages as well. Are you set on 6S? If your 220A or 240A esc can handle 8S then you can experiment with 8S. It's a slightly hotter setup, a little higher rpm with the 1390KV but with the right prop, most likely a smaller prop than if you were using 6S, it can be done with good results.

[Old School]

Many thanks gentlemen. I would prefer to keep with 6s. I was thinking a two blade prop but do have a liking towards a three blade.

Is there any advantage in stepping up to a 1/4" drive, still retaining the 4092 motor idea? I can utilise the stock 3/16" drive from the Osprey in another smaller mono hull, which I still need to purchase a drive for. The stock 3/16" drive will need to be removed to beef up the hull interior. Does a 1/4" drive consume more power to drive over a 3/16" drive shaft (less runtime)?

[CraigP]

Yes, there is higher friction with the larger flex shaft. How low no do you think the flex will be? The wind up is related to length. If it's over 15-20" in length, then I would be considering a 1/4".

Never mind this, I thought it was a 4092... if it's a 4074 or 4082, then 1/4" is probably not necessary.

[Old School]

With the 4092 motor on a revised mounting I think that there will be a minimum bend in the stuffing tube, so flex will be minimal.

[rol243]

normally with surface drive set up monos , there is a very minimal bend in the stuffing box so there shouldn,t be hardly any drag in the flex drive atall.
Old School , Hobby Supplies Melbourne have the high quality Aeromarine Flex Shafts in stock if your chasing a good one.

[Old School]

Many thanks, I just saved the Aeromarine webpage for products. No more expensive than anywhere else. I assume that they do postal orders.

[rol243]

Yes Tony from Hobby Supplies ships worldwide also his national postage is very quick and priced well too.