How to get into FE tunnel the right way.

[Tim_Duggan]

Congrats on the win Tony - excellent result considering the lack of water time on the boat! I never did get to see the datalogger files like we discussed - I just didn't seem to have a spare minute all weekend.

 

[Kris Flynn]

He had the cornering, I had the ponies...that was a great last heat!!!

 

[Tim_Duggan]

I heard the last one was a great race. I wish I could have mixed it up with you guys a little more than just at the start, but the handling in the corners just wasn't there. After the first lap I dropped waaaay back.

My first impression of P Spec tunnels - the throttle response / punch sure is different to nitro!

 

[hugh hargett]

Ok Can i ask a question here in relation to Brushless Electric motors

I dont run FE but i want too.

Why do most motor manufacturers not give a Watt Rating.

I can understand the whole Rpm per volt KV ect.

what i dont get is were is the load rating.

I know you can't pour 200 amps into an UL1 motor and expect

it to live. but how much is it designed for.

What i want to know is how do i choose a motor.

I want to understand what motor i need i dont want to be told

to go and buy an xyz brand 300000kv motor.

i see some brands that offer lets say a 2400kv motor and a 1800kv

which one is capable of making more power ?

We dont have Q or P spec in Australia we just

have 4s , 6s , 10s ect

i have no problems running a spec motor but i need to understand how they are rated

Greg

Hp or watts ratings are cool but torque is what turns the propeller. The term KV is the constant term a motor gives to derive its torque contstant or KT once you get the KT you multiply that figure by your derived amperage max to get the torque or strength of your motor which is what turns the prop. Typically the lower kv motor has more torque than a higher kv motor at the same amperage level. The stall current or the current youd see on an ampmeter when you stall the shaft would be your absolute current peak of the motor and pop it too.

Kt is derived by dividing 1 by your kv

Hugh

 

[ron upton]

as far as kv rateing etc are concerned dont forget u can get your unloaded rpm by multiplying the total volts times the kv...so a p spec running 14.7v X 2030kv = 29831rpm and that is good for about 52 mph or more with the right prop and boat.....

 

[Darin Jordan]

as far as kv rateing etc are concerned dont forget u can get your unloaded rpm by multiplying the total volts times the kv...so a p spec running 14.7v X 2030kv = 29831rpm and that is good for about 52 mph or more with the right prop and boat.....

Actually... the SAW record for that setup is a tick over 60mph...

Additionally, I've tested a LOT of UL-1 motors, and haven't found one yet that has a KV over 1970KV or so...

When you are doing your RPM calculations, you have to look at the actual voltage of the system under load as well. A 4S pack will charge up to 4.2V/cell, or around 16.8V. Under load, a good set of packs will still provide around 4.0V/cell for the first 30-40 seconds of so of the discharge under the loads you'll see with this system, so your RPMs would actually be based on right around 16.0V... say 15.6V, just to keep the nay-sayers happy.

So, a typical UL-1 system should produce around 15.6V * 1970KV = 30,732RPM...

And, Like I mentioned already... the NAMBA SAW record for this setup, as set last October, is a tick over 60mph (doesn't appear to be updated on the NAMBA site yet...)...

 

[ron upton]

i was being a little more general then all that lol

 

[Antonio Solo]

I run nitro tunnels, however I am getting the FE bug. I am planning on converting my HTB 290 into an FE tunnel with UL-1 motor. This brings me to my questions, It seems to me by the pictures I see that the OS strust seems to be the most popular. Does the OS strut have any advantage say over the K&B. I guess what I am really asking is which is the best strut for FE tunnel application: K&B, OS, Lawless, any other?

Thanks in advance, Tony

 

[RonShaw]

Tony,

Any of these lowers will work for the P Limited class. I would say whichever one you can get your hands on the easiest and at the best bargain, go for it.

 

[RonShaw]

Edit

 

[HTV Boats]

In the .21 size lowers the OS is better with the superior prop shaft and the trim is behind the hinge pin so that angle stays constant as you trim. The Lawless with an OS prop shaft is a nice looking unit but I feel the skeg flexes under load. The weakness on the K&B is their prop shaft that wears out of round in a hurry.

Mic

 

[Antonio Solo]

Ron/Mic

I appreciate your responses, running nitro K&Bs out drives I was aware of the shaft wearing out issue. I also have a lawless drive, but it also is set up for the K&B shaft, Therefore, I guess I'll break down and purchase an OS drive. Concerning the HTB 290 is it competative in the P-spec class.

Thanks again, Tony

 

[D. Newland]

A few video clips from last weeks Arizona Winter Warmups. We had some great tunnel racing and we've really come a long way in the last 3 years or so with these tunnels in FE trim.



Dan Proulx has the 295 running very well in the above link.

http://www.youtube.com/watch?v=f6syryfdSxA&feature=player_embedded

The purple boat is a Cobra. The natural wood tunnel giving a very good chase is a 295.

 

[HTV Boats]

Ron/Mic

I appreciate your responses, running nitro K&Bs out drives I was aware of the shaft wearing out issue. I also have a lawless drive, but it also is set up for the K&B shaft, Therefore, I guess I'll break down and purchase an OS drive. Concerning the HTB 290 is it competative in the P-spec class.

Thanks again, Tony

The HTB290 will do just fine as a P/spec boat. Build your radio/battrery box so you can shift weight from the back to forward and you will have a great running setup. Start with a Grimracer 42X55 and work up to an M445 if you can run it without overheating.

Mic

 

[Jeff Schindler]

Thanks guys for all the info! I had been lurking on this thread for about a year, but finaly got my boat together and it ran great. I'll share some pics and a vid when I get it right.

One question, can anyone share how they did the arming plug? You know the plug that can be pulled to remove power for retrieve boat and before and after your heat race.

 

[SeanKewley]

Thanks guys for all the info! I had been lurking on this thread for about a year, but finaly got my boat together and it ran great. I'll share some pics and a vid when I get it right.

One question, can anyone share how they did the arming plug? You know the plug that can be pulled to remove power for retrieve boat and before and after your heat race.

Here is one I made.

It weighs 2 oz without adhesive applied. I made it for a mono. I wouldn’t add one to my light weight FE rigger though. It is hard to find the space in some hulls to situate a loop. I only use a loop on that particular mono hull because it is difficult to tape down and I have the space to accommodate it. It may be fine on a tunnel where weight and room is not as much of a concern.

One thing to keep in mind… A loop such as this adds 4 more connection points where resistance builds and causes heat. The long wires add to resistance as well.

Glad to hear that FE has made it to Evansville. I may have to make a race or two this year.

 

[Jeff Schindler]

No FE in Evansville this year. We are trying it out as a open P class in Mt. Vernon, IL July 7 & 8

 

[SeanKewley]

Careful. FE is very contagious. It could spread to Evansville too

 

[HTV Boats]

No FE in Evansville this year. We are trying it out as a open P class in Mt. Vernon, IL July 7 & 8

Open "P" is that tunnels or any hull style?

 

[Dick Loeb]

Don't forget P Tunnel has a MAX of 34 inches on hull length