Lee_

Hi,

I might have possibly created the World's Fastest EDF powered R/C boat.

Does anyone know the current record?

Thanks

JS440

My Feedback: (10)

No idea. Let's see it.

Lee_

I can't share anything until I've made at least 10 posts. Seems a silly rule.

Does anyone have any EDF boat speeds??

Hydro Junkie

Not really, if you know the reason behind it. That rule was installed four or five years ago when the forum started being slammed by people advertising their products in single post threads with lots of pictures. Next thing we saw was people had been swindled out of their money by these "advertisers" with no way of getting it back. After several complaints, the admins went through, cleaned out all of the posts that were clearly just for advertising a non-existent product, and installed the 10 post requirement. Needless to say, the problem went away almost immediately since the people that were putting the posts up now had to actually become an active member and that was something they didn't want to have to do.
I return you now to your normally scheduled thread content

Lee_

Advertising non-existent products is surely not something you'd want on any forum.

3 down. 7 to go...

Then I will be able to share a picture of my EDF boat!!

Lovely weather we're having right now in the U.K.

Hydro Junkie

Lovely weather? What makes it lovely? In my neighborhood, we had scattered clouds and 29C yesterday

Lee_

It's about 24C here and it's not raining.

For England, that's lovely weather!

Got RPM

Go here, start a thread then make enough posts to meet the minimum.

https://www.rcuniverse.com/forum/test-posting-forum-72/

AFAIK there is no official “record” for EDF boats, just semi-official airboat speeds. That record is in the high-90s/low-100s but uses GPS speeds so not comparable to water-prop boats. I’ve heard a few folks mention EDF speeds in the 40s though.

BTW it was 43* here today…..
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Lee_

I have 43.43mph out of my scaled prototype. The full sized version (1.7x) is now fully ready to go which is designed to beat the airboat speed record. It's also an EDF. So certainly will be the fastest EDF if my prototype isn't already.
I guess I'll just have to wait and see if it gets contested.

Ron Olson

My Feedback: (1)

There is no official sanctioning body that includes EDF and turbine propelled boats, not even airboats. Speeds would have to be recorded with official equipment, not just a GPS dropped into it.

Got RPM

I'd love to see your model, it sounds interesting. I've built many airboats over the past 50 years but only one EDF. I've held many official FE speed records with water prop boats and know the current world record holder very well (206 mph), but never tried seriously with my airboats because they were not recognized by any serious governing body. Perhaps I missed out.

The "official" airboat speed records were compiled by a fellow in Florida who ran an R/C airboat website and chaired the Radio Controlled Airboat Association (RCAA) but those have been closed down for years. The rules were that you used a GPS and had to video the entire run from turning on the GPS showing no max speed, making the run, pulling out the GPS and showing the max speed without any interruptions. Not the best method but for what he wanted it worked. Since there is no recognized governing body now, you can claim whatever you want. While the RCAA posted a top speed record of 70.4 mph, many airboats both fuel and FE have exceeded that speed since.

https://web.archive.org/web/20111017...peed%20Records

This is the fastest one I know of, but we are at the mercy of GPS and video and his integrity.





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1QwkSport2.5r

I held one of those RCAA speed records for my .20 series SI3 3-point Hydro airboat with a Jett .35 BSE engine. My official record was 49.6mph I think which I bested a couple weeks later with 55.1mph. Not bad for a boat I scratch built with no true dimensions and wood I pulled out of a trash dumpster. .

Lee_

Thanks for the replies!

I got 48.41mph today on a test run with my full sized boat.

Only 50% throttle on the stick and it was still accelerating away. I had to throttle back as I ran out of lake.

I'm getting some lift at the rear which I'm adjusting for the next run. Quite lucky really as if it had not lifted up, I would certainly have not backed off the throttle and it would have ended up in the bank.

Got RPM

That’s a common mistake, running for speed on too small of a pond. Official SAW courses for water prop boats measure through 330-foot traps, plus run up and slow down room. The lake where many records were set was about 2000 feet long and accommodated speeds in excess of 140 mph.



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Lee_

This needs more space than that as there is little to pull it down off the plane other than wind resistance and some surface drag.
Prop boats have a large wedge rudder and usually a turn fin.

Lee_

Yay!! 10 posts

Hydro Junkie

But neither the fin or rudder have enough drag to really slow the boat down quickly. The actual braking is due to the prop. As the prop slows, the blades no longer are moving fast enough to push the boat so water that would have been drawn through the prop is now hitting the front surface of the blades, acting like a parachute and slowing the boat

Got RPM

Even with a water prop the boats will coast a long way without a turn fin, my riggers always did. In early FE days racers would use a car ESC with a brake which helped, but not in a long time since modern car controllers don’t have the amp capacity for a SAW boat.

A successful remedy for that has been the fitting of air brakes, several record-setting SAW boats have used them up to 140 mph. Still, the best solution is to run on enough water, which has its own challenges like wind and waves.




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Hydro Junkie

Not disagreeing at all. Just making the point that a rudder or fin won't slow a boat that much and that the prop will do so better. That said, speed and distance are relative, higher speed requires more stopping distance. Then again, we have 1/16th mile speed runs on a man made lake that's 1367 feet long and 326 feet wide where I don't remember seeing more than one or two ever hitting the end of the lake. When the boats cleared the second trap, it was hard right on the rudder and pull a tight corner to slow the boat down