In a word, NO. While his boat looks similar, it is actually running on the water and being held up by water pressure on the bottom of the sponsons. A sport, scale or full sized hydroplane is actually supported by air pressure under the hull. Something else that is different is his boat should turn equally well both ways where mine doesn't like to turn left. In fact, too hard of left turn and mine will be upside down

Hydro Elitist! (you missed the little curved planes he designed under the sponsons)

And the final nail in the coffin for RC because of drones - don't look for relief from Remote ID:
https://www.thedrive.com/the-war-zon...porter-onboard

Perception , , , , life is all about perception . Since the "Crickets" thread here seems to be our little thread about nothing , here's something other than nothing to ponder ;

Have you seen the logo affixed to the newest Mars rover ? It's supposed to honor those in the fight against the killer 'Rona , but , , , how do you think the Martians are gonna perceive it ?

Maybe they'll see it and think "Hmm , the blue planet is just full of big ol tasty snakes , we should invade them and fill our freezers full !!!!!"

Or maybe they'll take it as a war threat and launch a preemptive strike "They're gonna send their billion snake army to invade us , we must strike them NOW !!!!!"

;) Yep , , it's all about the perception .....


https://cimg6.ibsrv.net/gimg/www.rcu...a8d6a670a1.jpg

Hmm, "Killer Rona" and perception - a Google search brings up a supplier, "Rona", that sells Roundup weed killer.
Martians might see Earth as just full of weeds.

Not a hydro elitist at all. Just stating a fact, the boats are different in how they work. Echo has described a "Bluebird" style hydroplane with hydrofoil characteristics that lift it out of the water, thus reducing drag and increasing speed.. My boat uses air pressure from the boundary air layer that's forced under the boat to reduce drag by lifting the boat. Same result from different methods.

The guy is aiming to beat the RC boat speed record of 103 MPH. How fast do your hydros go?

I've had mine around 60 MPH on a 1/5th mile oval. Even the fastest boats I know of won't go much faster on that short of course. Hate to say it but 103 is no where close to the record. The record is around 135MPH, set by a team of German engineers/R/C boaters a few years ago with an electric powered rigger style boat

Should have said RC "Airboat" record. The absolute RC boat record is claimed to be 206 MPH:

Hydro, just spitballing here and as you know boats aren't really my thing but flight trimming an airplane certainly is. I can't help but think that the fluid dynamics between a boat and airplane are very similar. I recall you stating that CG is crucial to boat performance so my theory may be at least partially correct. As with anything powered by a reciprocating engine there are forces created by the rotating mass. Obviously on an airplane you have the crankshaft, prop and spinner. Props themselves produce an uneven thrust vector. These are just a couple things that need to be considered when trimming a pattern model. From my limited experience with boats I don't see why the same things would apply however the values would be different. The way we compensate for these phenomena is the use of offset thrust angles and sometimes offset lateral balance. The lateral balance offset I would guess would be the biggest benefit due to the gyroscopic forces imposed by the heavy flywheel. Or I could just be all wet ( ha ha pun ) and this has already been thought of ( most likely ) and I will learn a little bit more about boats when I read your reply.

FWIW, here's the list of current Straight-away (SAWS) record holders. Average of 2 passes through the gates.

::: The Official Site of the North American Model Boat Association :::

Current fastest in US is 142.940 for a 10S hydro (outrigger) Electric boats are generally faster than IC powered boats. Top gas boat speed on same course is 128.205.

IMPBA is another US organization, but I'm not sure what their numbers look like. I held a couple og Fast electric records (T mono, S mono and T offshore) for a short time. Guys keep going faster.

The 206 mph was set in Europe

I can't imagine that, i can barely track a big turbine jet doing 180

Edit: For the word nit pickers, I can track my jets just fine, just making a comparison of the amazing skill it takes to run a small boat that fast.

You're not "all wet", in this case anyway.
The rotating mass effect is just as, if not more so, prevalent in the boats. The reasons for this are:
1) Boat motors turn much faster than the equivalent size aircraft motor. A n OS 65 AX aircraft engine will spin a 12X6 to 14X6 prop up to 16K, that limit is partially due to the prop tips going supersonic and becoming ineffective if it goes any faster. The CMB .67s I run in my scale boats will turn 28K while my Nova Rossi .21 will spin up to 35K, twice as fast as the O S .15LA fitted with an 8X4
2) Unlike the longer aircraft props, a boat prop blade is short and wide, my boat running a 60mm prop with a blade area of around one square inch per blade. Also, unlike a plane prop, the props we use in the boats are set up in what can only be described as an "overdrive" configuration. Going back to the O S 65, it spins props that only pull the plane up to half of the prop's diameter for each revolution. For each revolution of my boat's prop, it pushes the boat 1.5 times the prop diameter, or 90mm.
3) Unlike an airplane prop, which is constantly loaded on all blades by the air, my boat's prop is only half submerged when running. Between the air pressure under the boat and the design of the prop blades, the rear of the boat is lifted until only the bottom half of the prop arc is in the water. This means the prop is doing several things at once for each rotation:

• it's pushing the boat forward
• it's lifting the boat upward
• it's trying to push the boat's rear to the left, inducing a right turn in what's called the "paddle wheel" effect

4) Since the prop blades are each being forced to enter the water during a rotation, the effect is an uneven lift, the left side of the boat being lifted more than the right. This can be compensated for by offsetting the motor to the left, installing the fuel tank(s) to the left or adding weight(usually in the form of flotation foam or lead shot mixed with epoxy) in the left sponson. If the boat tends to want to fly, the lead/epoxy can be split between the sponsons with a majority of it going into the left side
5) Unlike an aircraft motor, a boat motor uses a flywheel that can weigh up to half of the total motor's weight. This mass is used to keep the crank spinning as since the prop doesn't have the mass to perform the same function as it would on an aircraft.

Now, to get into other control surfaces that come into play, and the misconceptions associated with some of them, I'll have to cover them one at a time:
1) Vertical stabilizers.....These serve one major function, directional stability. Before the days of the now common horizontal wings, the boats were fitted with a vertical fin with a rear section offset to the right. This was to help keep the boat going straight and reducing the work load on the driver since the boats have, with two exceptions that I know of, never had any kind of power steering. Since 1973, with the introduction of the Pay'N Pak, the vertical stabilizer(s) have taken on a second function, a mounting point for the horizontal wing
2) Horizontal stabilizer....This is the most misunderstood part of the boats. Many, incorrectly, think it's used to lift the back of the boat out of the water. This couldn't be further from the truth. The horizontal stab is actually a "trimming device", used to adjust the boat's riding attitude based on testing and water conditions. This is only adjustable on the beach and, regardless of fill sized or model, it is not movable while running.
3) Rudder......This one would seem to be self explanatory, but appearances can be deceiving. The rudder actually controls how much the rear of the boat is allowed to "paddle wheel" to the side and, when making a race course turn, assist the prop in pushing the rear of the boat to the left(R/C boats anyway, full size would be to the right). The rudder is also the location of water pick ups used for engine cooling and speed sensors
4) Turn or Skid fin.....This one is the only surface that actually does what it's called. The fin, located at the rear of the inside sponson(left for full sized, right for model) prevents the boat from sliding or "skidding away from the buoy line and acts like a pivot point the boat turns around.
5) Canard.....This is the only aerodynamic surface that can be controlled by the driver. It is used to control the attitude of the boat by changing the lift at the front of the boat.

Actually, when running "solo", tracking the boat is easy. Just look for the forward end of the "rooster tail" as the boat will be at that point. It's when you have several boats all together that things get hairy since it's harder to see where a boat actually is when it's partially obscured by other boat's skid fin water or rooster tail

LOL, everything you ever wanted to know about boats. Isn't there a forum for this? Since there's no water here I really can't play.. Want to talk about High Powered Rocketry? How about Smokers , pellet or wood which do you prefer?

Mike

Was just replying to Speed's post which kind of asked the question. Just to remind everyone, this is what he posted:
Hydro, just spitballing here and as you know boats aren't really my thing but flight trimming an airplane certainly is. I can't help but think that the fluid dynamics between a boat and airplane are very similar. I recall you stating that CG is crucial to boat performance so my theory may be at least partially correct. As with anything powered by a reciprocating engine there are forces created by the rotating mass. Obviously on an airplane you have the crankshaft, prop and spinner. Props themselves produce an uneven thrust vector. These are just a couple things that need to be considered when trimming a pattern model. From my limited experience with boats I don't see why the same things would apply however the values would be different. The way we compensate for these phenomena is the use of offset thrust angles and sometimes offset lateral balance. The lateral balance offset I would guess would be the biggest benefit due to the gyroscopic forces imposed by the heavy flywheel. Or I could just be all wet ( ha ha pun ) and this has already been thought of ( most likely ) and I will learn a little bit more about boats when I read your reply.

Mike, if you want to give a mini-lecture on rockets, feel free. Never got into them as I never had anyone around that could actually give instruction on how to build, the safety protocols and what motor should be used for what. As for smokers, I have a shop about a mile from my house that I can get smoked meats, Texas style. Needless to say, I have to get there as early in the day as possible as they normally sell out in three to four hours and then close up shop.

It was a joke. Back to your regular programing.
Mike

Wasn't sure if it was or wasn't, figured I'd respond anyway, just to be safe. BTW, what wood is normally used for Texas BBQ? The shop by my house says it imports wood from Texas so.....

It varies from place to place. I like mesquite.

MIke

:p Getting pretty close , it's now legal for recreational use here in Ma. so those lil green men can smoke & toke till their hearts content here ,

and not get clubbed like seals by the man , like back in the 70s ! :eek:

:cool: So , it was nice of the AMA to send me that survey regarding the magazine , it appears from the questions that they are gauging interest in going all digital VS a printed hardcopy . I answered that an on line only version would be fine with me , and to include more build articles .

Anyone else here get the survey ?

Anyone else find it funny that the AMA feels compelled to ask our opinion on an outdated, money-bleeding rag, but completely leave us in the dark on important issues?

If history is an indicator, they will receive feedback from about 6% of the membership anyway....why not just look at the fact that print mags are outdated and they can much more efficiently disseminate the same information digitally....it’s a complete no-brainer!

Astro

Guys, chill a bit and think about it. They are asking a question to see if they NEED to make a change, not to see if the membership wants them to make a change. They are going to do what they want, regardless of what information they are given and then spin it to make it sound like they are doing what the membership wants. To do otherwise will be to go against character and THEY CAN'T GO AGAINST CHARACTER

I honestly am happy they sent it , and I'll be even happier if they post the results ;)

Are you holding your breath yet? :p

I'm still trying to get a straight answer on how the AMA Charter Club Flying feilds being exempt for the remote ID thing is progressing. Just can't seem to get one. Both feilds here in town are Glass G airspace.. Seems like that would make it easier.

Mike