Wing In Ground-effect craft

[El-Kablooey]

Boys, are we seriously getting somewhere with this?

I do believe we are, Bruno!

It may take some time, but I WILL be flying one of these suckers within the next year or so. I do not see any major difficulty in this.

The only problem I see with lockys wrapped around the wings is heat. You could easily shape the engines to keep them from filling with water before takeoff. I guess losing one engine could be a problem too. I don't think you would instantly crash though, just wouldn't fly straight. Like I said before, I'm gonna crash anyway.

[OctoberRust]

Boys, are we seriously getting somewhere with this?

I do believe we are, Bruno!

It may take some time, but I WILL be flying one of these suckers within the next year or so. I do not see any major difficulty in this.

The only problem I see with lockys wrapped around the wings is heat. You could easily shape the engines to keep them from filling with water before takeoff. I guess losing one engine could be a problem too. I don't think you would instantly crash though, just wouldn't fly straight. Like I said before, I'm gonna crash anyway.

Not flying straight is a major problem - because most of your control surfaces sorta depend on having air flowing in a certain direction, it's very likely that you're not going to be able to recover control, and you're going to go into the water in an attitude that is not conducive to survival.

[El-Kablooey]

I'm tellin ya man, crashing is not going to be a life threatening situation in the ship I build, it is going to be more of a funny thing.

[Rossco]

hey Joey, and all following along.

Your comment, "crashing is not going to be a life threatening situation in the ship I build, it is going to be more of a funny thing"!!
I wouldnt be so sure of that.

As an update, i now have a small, very nice, glass boat. I dont like its name, and will have to change it to something like R&R... for two reasons. One, Rossco & Ryan, my mate who is into this project with me, and the other... Rescue & Recovery! As this will be its new job.

Yes, i agree with you. It will be "priceless"ly funny for all on land, watching. Although not for the pilot!
If you get one of these going to the extent of posibility of a crash, then i advise you have a recovery plan.
Our new "proper" boat has a 25Hp johnson, foward control, outboard.
It gets up on its plane almost instantly, with full throttle, and really flys.
A crash even at this speed would be very dangerous! letalone a flip!
This boat being old, and fiberglass, is very heavy for its size. Just imagine how fast the minimax will go, since you can cary it on your back!

We also acquired a 40Hp fully rebuild Murcury. Very Nice!!! you should hear it run. The idea of this is that it is a transplant for the "R&R" for resale purposes, providing the 25Hp for the minimax at worst, no cost. It will probably even make us money considering what we spent on them.
I nearly feel bad for the guy, he needed the money, but had spent soooooo much on this engine.

The 40Hp will be going on one of the minimax's, just for a test run or two, to test hull improvements, although, i cant see more than 25Hp being able to be used without it landing on its lid. The "plans" which i really didnt go by much, say that its good for a 3 - 18Hp engine. One of the photos that Joey uploaded of a minimax had a 20Hp on it, so i just had to go a bit bigger than that!

The other notible conclusion that i have come to is that i realllllllly want to go to thrust drive sooner than i had planned.
A couple of trips up and down the river in a nice secluded spot, with a bit of fishing inbetween. (shoulda seen the monster i caught!..... but it got away. Honest!) anyway, we got a bit cocky and let out gaurd down about our new boat, and BANG. hit the bottom. The prop took a big mouthfull of nice rocky riverbed, and smahed the sheer pin. Really wrecked the joy of it all.

With the little minimax hydroplane, probably operating in about an inch of water at little over walking speed, it is counter productive to have a whaping great leg hanging out over the back into the water. It would be invincible with a ducted fan or two on it.

Ah, crap... i just noticed that this thread has moved along a little, exacly a page and i didnt notice, so i had only read that last couple of posts. Makes a little more sence now i go back and read it all!
Anyway, what ive said is still relivant, and good if nothing else for an update.

Bruno, i expect your comment was exited disbelief, not discouragementent... i wouldnt think that is you? Your welcome to pop over to Auz, and check out progress any time you like! You would just have to be subjected to some test pilotings for the reall experience!

Ah, and i meant to thank M.
As usual an exeptionaly layd out post that was most infomative.
Ducted fans would be logicaly the next step in progress with this. Jumping straight to PJ power is a little premeture i would think.
We'll have to wait for Bruno to come up with something suitable!!!!

Rossco

[milisavljevic]

Hello Rossco!

Thank you for the kind words. This is only my opinion, but if measured in terms of dollar cost and mechanical complexity,
valveless pulsejet propulsion is a better option for a project like yours. A ducted fan solution will be more economical,
with respect to fuel costs, and the idea of reciprocating engine technology is as comfortable as an old leather jacket.

Pulsejet pro and pulsejet con... Sometimes, it is only a matter of properly selecting one's perspectives. C'est la vie!

If it were up to me, I would go for a pair of close-coupled pulsejets, derived from either the Ecrevisse or the Escopeta.
In any event, good luck with your project. If you do decide for pulsejets, please let me know if you want any assistance.

Best regards,
M.
__________________
"What? He didn't mention that Chinese pulsejets will also work? Oh, wait, he just did."

[Bruno Ogorelec]

Rossco, yes, that was excited disbelief :o) I mean, this thing really looks like getting off the ground, if you'll excuse the pun. I am very excited.

The reason I want the engine 'wrapped around the wing' is the benefit of giving assistance to lift. Many WIGs, especially the Russian designs, blow air under the wings to help the air cushion 'blow up' so to say. It probably allows the craft to remain in ground effect down to very low speeds, too.

It would not have to be done crudely, so that a half of your engine is in the water -- some tinkering with layouts can surely provide an elegant answer. Just off the cuff, I can imagine the stretched-out Lockwood forming a kind of a leading edge of the wing, with the 'intake' and 'exhaust' bent back, one to blow below the wing and another to blow above. I mean, pulsejets can be bent and twisted and pretzeled any way you like.

We have to be inventive here, as we are breaking new ground anyway. Might as well try new stuff.

Bill Hinote has recently revived the Pegg-Makowski pulsejet helicopter engine layout idea (for a different purpose). Here's how it might be used for a WIG craft.

This pod with two augmented engines might be a canard with adjustable pitch, so that you could vary the thrust angle slightly. It could blow under the wing at startup and above the wing as the speed builds up. Or something. But, the main reason I brought this up is because it gives you off-centerline thrust without the danger of engine-out instability.

[OctoberRust]

I like it, Bruno.

Two of these rigs, one forward of the wing, the other just aft of the midpoint. Variable pitch angle on the front ... that could really help with the takeoff speed issue, as well ...

One concern, though ... we're still talking about using styrofoam and GRP for the main construction elements in this, aren't we? These things like what you've described are going to have to be -inside- the aircraft ... and it just seems like a red-hot piece of metal with styrofoam wrapped around it is going to be something of a threat to structural integrity? (And something of a fire hazard, as well!)

The other advantage of this - as you said, it's not going to impact your stability so adversely if you lose an engine. AND even better, since you're off the centerline ... you can get by with a traditional single vertical rudder, which will simplify your control rig immensely.

[El-Kablooey]

After alot of thinking, I'm kind of leaning towards Bruno's suggestion of fabric wings. I talked to a few guys and got to take a look at a plane built this way the other day. It is very sturdy, and super light. The plane I looked at, built by my fishing buddy Alan Lowery, is called "The Cloudchaser" you can check it out at http://www.ronlowery.com. This thing weighs just over 1000lbs, most of that weight being the 2 292hp ROTAX engines. Yeah, 2 of them! The plane is built around a light aluminum frame with stretched fabric wings, a real performer. This would be a fairly easy and inexpensive method, and you won't get any lighter. One of my goals is to keep the wing loading down to less than 4lbs per square foot, that should give a very low take-off speed. It would also help to minimize risk of injury in the event of an unexpected landing.
I was planning to use a couple of big chinese engines, via Eric's plans (Thanks Eric!) Probably mounted alongside the struts that will support the tailplane.

Hey, has anyone ever moved the intake on a chinese to the front, like a linear engine, and then bent it like a lockwood?

[Rossco]

Hey Joey!, and all,

Well, the minimax went in the water for the first time yesterday.
There is no doubt that we shall be able to make these things fly without too much difficulty.

Couple of quick notes for now.

ONE, Joey. Stick an outboard on that thing of yours and get it into the water. It needs some reall mods if you are going to get it running on anything other than direct horsepower!
It just throws power away all over the place, and i think that you have some more boating experience than me, so id like to get your oppinion on the mods.
Im just shooting in the dark atm, with nothing other than seat of my pants feeling. (litteraly, it doesnt have a seat in it yet)

So, basic point form.

The biggest note, 20HP just isnt enough. Well, it sure goes like a bat outa hell, but it just doesnt have that scary, "crap im going to die" feel at top end.
Its just too stable. Sits flat as a tac when on its plane, no matter what the trim.

Points skyward LOTS to get over onto its plane. This is in no way out of control either, just like a mono on a bike. Just shift your weight over the front, and it goes over.

Accelleration, from the instant it goes over, is breath-taking! with in a few meteres its up to full speed! Very hard to race any other boat, cause they have to be going full speed at the instant you get onto the plane.
So, first step i suppose, is prop it up a bit... then ill go for more power.

Super stable in the water when stationary, i can walk all over it, even with the heavy engine on, and full of water.

Self bilging! just take of fast, and it all pours out the back.

Even though it threw me twice, its got no feel of flipping! At full speed, over a decent wake of another boat, it gets pretty good air, and bruises you a bit on landing, but doesnt feel like its going to go over.

NO STEERING! With one centre keelson, it slides all over the shop. It will turn slowly with a bit of speed, for about 90 deg. then it just slides, drops speed and stalls on the spot. Turning then is easy, although you gotta get it back up on its plane.

More later.

Rossco

PS let me know what you think about the keel set up. It needs something drastic. What is in the plans just doesnt work.

[El-Kablooey]

Kick ass, Rossco! I haven't even gotten mine painted yet, just been too busy. It is too cold to be swimming here now, I won't get to test mine out good for awhile.

I thought that keelson in the plans might give some trouble, being right in the center on a short little boat like that will cause ventilation of your prop, robbing it of power when turning. I am using 2 keels, one on each side, about 2" tall. I don't know how well this is going to work, but I hope they will give me enough grip to be in control but still able to slide a little. They shouldn't mess with the prop for either. I hope they will help to trap a little air under the boat too. You could also try a shorter, deeper keel towards the front of the boat, ending well before the back of the boat. Some people like aluminum fins around 8" long and 6" deep. Not me though, I want to be able to run in really shallow water. I really hate to have any keel at all. With PJ power I hope to play with mine on some local whitewater rivers. I think it would be fun to run upstream, skipping over rocks and scaring the hell out of some rafters with the ungodly noise.


BTW, If your boat's bottom is going to see any abuse, a trick builder's use on the Mckenzie driftboat's, used for fishing fast, rocky mountain rivers is to mix up a bunch of graphite powder with epoxy and cover the boat's bottom with it. It's hard and slick, and the more you drag it the slicker it gets.



Congratulations on the MiniMax! Put some wings on the thing!
I'll have mine ready to go come spring!



OH yeah, I was thinking of putting a jet-ski type seat in mine, intead of a bucket seat. What do you think? I was thinking that being able to shift your weight around easily might be benefecial??????

[El-Kablooey]

One more thing, generally the cavitation plate on your outboard should be level with the bottom of the boat for best performance, the plate may need to be slightly deeper on this design, play with it and see where it works best. The engine not being trimmed right can cause alot of problems.


Hope some of this helps!

[Rossco]

Hey all,
Im back from a very rough weekend.
All maner of nasty things have happened.

First of all, a good word in for my mate, who got himself bashed up, in hospital with bleeding on the brain and all. Fingers crossed.

The Minimax, is in the bad books!
Its still stuck on the top of my truck, banished from the water, although i cant even get it off to hide away.

I am now nursing broken ribs, cuts to the bone, and brusing from head to toe.

I got the turning problem sorted with some test fin/keel set up. But yes Joey, cavitation is definitely a huge problem still. Ill be taking the centre keelson off compleatly.

The next thing that i was working on is the center of gravity of the craft. This will be a very hard problem to solve with thrust power btw!
As far as i could work out before i hit the water, the CG has to nearly be at the transom in these boats. i would say about a foot foward?

To test this, i was "surfing" on the minimax. Then letting my wieght back over the engine. I could hold my whole weight on top of the engine! This sat her up nicely, and i really got some more impressive top end.
I would guestimate, up to about 80km/h ? Hard to judge, although it was really getting along!
Very happy with this, and maybe a little over exited i jumped foward, to pull the throttle back.
Pulling the power off tends to shake the engine back and foward quite violently, and this time from extra speed was even worse. I was still crouching, and going very fast, you understand. I panicked maybe, just a little, and did the worst thing that i could have done. Pulled the power off compleatly! This instantly snapped the engine into a full lock turn, and threw me out to a great slide across the water!
Biggest problem was that i must have bumped the throttle back up and the boat took off again. This i thought was not going to be good for the boat as it really was getting some speed up on its own.
It then proceeded to do a nice turn, and come straight back for me. (not to pick me back up by the way)
All i could do was charge it with my arms, to try to deflect it. This did not work in the slightest! i just didnt realise how fast it was going i think.
It smashed me under the water, driving the engine leg into my ribs, and the prop into my hip. My shirt coped the rest, tangling around the shaft to stall the engine.
Not a good feeling hanging from the prop, being winded and not knowing how bad your damaged under the water surface!

Im OK really, VERY lucky!
I will get things done in the right order when im up to it again. First thing is the kill switch cord, attached to the driver.

Joey, that boat of yours really needs some safety and ride testing before you go for "experimental" power plants too!

Rossco

[Mike Everman]

Oh my God! Good grief! What a story. You are nuts, Rossco, and a very lucky guy. Get some rest. I hope your buddy gets better, too!

[Viv]

Christ on a crutch mate!!! I thought I had taken some headers but that takes the biscuit!

Big style!

I am in awe;-)

And hey what happened to your buddy?

Viv

[Viv]

hey Joey, and all following along.

Your comment, "crashing is not going to be a life threatening situation in the ship I build, it is going to be more of a funny thing"!!
I wouldnt be so sure of that.

Rossco

Hey mate you just had to say you know you didn't have to demonstrate it as well:-)

Viv
Ps see I was paying attention:-)