Spec Electric 7.5 Nitro Replacement

[Kris Flynn]

Who did you get thr "Vision" off Fabian?

 

[Fabian Hill]

Hey Kris,

bought it on ebay was cheap as can't afford ones from US although I like those ns295... they look nice.

I'll be looking for a 3.5 size hull and outboard leg soon though if you know anyone ?

 

[hugh hargett]

At this point I'm not sure the outboards need any extra cooling. After all, the motor is connected to a big, water cooled heat sink (the lower unit) and gets spray plus air ovet it. The above Q power plant is now installed in a Mutt II sport 40. The motor is still exposed but is now under a cowel. That's the same setup I ran on my Scorpion powered 1/8 scale boat. If the current is kept to a reasonable level, heating shouldn't be a problem. We'll see how that works.

The Scorpion motors have been getting more expensive. I would be interested in how some of the other 1000 to 1200 KV outrunners are doing. The other problem with the Scorpions is that they are conservatively rated. Both of these mean they might not make the best "fuse".

Lohring Miller

The t-600 is staring you right in your face 350 grams 4.7 hp 1400kv and trust me you want one of theese scorpion upgrades the more heat it can take the harder you can push it plus after the upgrade it wont mind running for six hours straight or better. Theese would be the same upgrade that the military has done to them before they put them in surveilance drones but if your not interested suit yourself but whe you see mine all done and finished your mouth will .

Hugh

 

[raptor347]

The t-600 is staring you right in your face 350 grams 4.7 hp 1400kv and trust me you want one of theese scorpion upgrades the more heat it can take the harder you can push it plus after the upgrade it wont mind running for six hours straight or better. Theese would be the same upgrade that the military has done to them before they put them in surveilance drones but if your not interested suit yourself but whe you see mine all done and finished your mouth will .

Hugh

Lots of interesting stuff being done in the sUAVS world. Just haven't needed to go there, the old don't fix it if it's not broke theory. When we first started playing with the scorpion motors they were pretty cheap for the performance delivered. With the price increases, other options start looking attractive for the budget minded racers. If we're talking open motor classes, there are better designs out there.

One of the nice things about the existing hulls, a good Q system just isn't being pushed very hard to motivate a 7.5 size tunnel. Until the hull design catches up with the power available, you can't harness what you can get out of the stock scorpion motor (no idea about the T600, haven't run one).

If you really want to go for efficiency/performance on an open motor P or Q tunnel, a custom wound 19xx series Neu in the heli config is worth a serious look. But then we're back to spending money again.

 

[hugh hargett]

wats up Brian?, Loh pmed me. Id like to try to get things into you guys hands coz I know yall test test test and bring back numbers not opinions that why I love you both so much :wub:

My guy can can custom wind your existing out runners if you need pm me

Hugh

 

[raptor347]

Thanks for the offer. I've got all the stuff here to wind anything I need. Started winding brushless motors 15+ years ago. Wound a good portion of the old Aveox competition motors before Steve started building his own stuff. Somewhere around here I've still got the carbon stuffed, stainless tube rotor shafts I used to make (save weight in the F5D motors) and a stack of 1409 Aveox rotors in with increasing air gaps in .005" steps. I sort of miss the days when we had to build everything (where's that "feeling nostalgic" emoticon), there was a sense of accomplishment when you made it to the World Champs.

Anyway, the biggest advantage to the outrunners for outboards is packaging (cheap doesn't hurt, but they aren't cheap anymore). They keep the weight low and cool themselves fairly efficiently, heli guys like them for the same reasons. The drawbacks being the gyro effect of the heavy/large diameter rotor bell and what I consider sluggish throttle response. That sluggish throttle can be a help if you have a habit of running props that are a bit outside the sensible range.

Now if you could have the packaging and torque of the outrunner with the efficiency and lower rotor inertia of a high end inrunner 24 slot, 8 pole, hollow rotor), you'd have a winner.

 

[hugh hargett]

 

[Fabian Hill]

Bit of an update on update on the new hull I put my running gear in a nice smooth day running and a rough windy day with a crash .... and a few questions ....

So here is the smooth day, bit of porpoising but first run on this hull so fairly pleased :



Needless to say a bit of damage, so have now repaired it and doing the best I can to make it a bit lighter and re aranging servos batterys ect, I will be doing the same mod to the cowl as Kris Flynn and I saw someone else do it where you join the cowl to the hull then cut out a lid and then can eliminate the weight of radio box, will also move battery to the back and servo forward.

I'm still running lawless7.5 lower with scorpion 1100 KV 6s Dr Wayne Battery and swordfish 200

Ok the questions I have :

On a vision .40 what should cog be ?

What height do you guys run the bottom of the prop shaft roughly above bottom of sponson ?

I have 3 types of servo here what should I use ?

Turnigy Model: TGY-1501MG Voltage: 4.8~6.0v Speed: 0.16~0.14sec Torque: 15.5~17.0kg/cm Weight: 60g Size: 40.7x20.5x39.5mm ( would like to use this but not sure if enough power grunt )

OR

Turnigy Model: S8166M Bearing: Twin Gear Type Metal Speed: .21 deg/sec Torque: 33kg-cmWeight: 154gSize: 75 x 59 x 27mm ( This is what I have been using works great but a bit heavy / bulky )

OR

Hitec HS 755 HB ( this steers my dragcat at the moment and if I need to use this then I will and could put the heavy turnigy in the dragcat )

What are the advantages of using that pull pull cable steering with the wheel on the servo compared to pushrods and where do you buy that wheel from ... ?

Is it possible for someone that has a lawless 7.5 lower to post some photos of an oiler setup ?

Ok well that's me ... lol hope that's not too many questions ... really happy with the setup and again thanks for everyone's help in the beginning when I was buying parts and setting up and also had no clue now I have a small clue ... : )

Also anyone reading this in QLD I'm out of work and need a job !!!

And if someone needs some props or other stuff beed blasted I have access to a really good machine so can do them for a small fee.

Cheers,

Fabs

 

[RonShaw]

Does that concrete wall surround the entire pond??? Ouch!!

 

[Fabian Hill]

Hey Ron, no just the side I decided to hit ... lol

The other side is a gated housing complex so I don't venture to the other side much otherwise will be a long swim ...

 

[John Solway]

well this thread encourages me to throw one of my xt460's together! thanks guys

 

[Greg Johnson]

I'm interested in any updates to this thread. Are there any updates as to what motor, ECS and battery to run in a 7.5 size hull today?

 

[Kez]

Much like Lohring a few of us here are working 45 size FE's. The P-Spec seems to have power to put it into a mod 21 class so going to a straight "P" on 4s or "Q" on 6s should definately require a 45 size hull. Batteries like Hobby Kings we have been using seem to work well but I can see some Grimracers and Hyperions in the future.

In rigging a few FE Tunnels I like the batteries as far back against the transom as possible. Makes it easierr to control CG. Just my opinion.

Hope we get some more feedback here from others and as I test on thje water I will update. New ground here.

Mic

View attachment 28071

Mic, That's a nice looking boat. Can you tell me where you get the outboard cowling? It looks like an International Hobbies outboard cover.
Thanks,
k

 

[HTV Boats]

That is an old cowl off an AMPS outboard.

In response to Greg Johnsons question on updates for 7.5 FE hull to FE I have a lot of info since this 10 year old thread was started so I will post a new thread today when I have some time to type.
Mic