Its going really well. Steering is good too. -If you can get enough ground clearance without the tape it should have much less drag and therefore be faster. I use an angle of 45 deg for the air curtain which seems to work best, and a 5 -10mm wide slot. The idea of the tape was to allow it to flex without being damaged, but I've stopped using it now and just have a thin strip of plastic.
It should stop a few mm above the base so it doesn't catch on things.

Right on, i changed the tape to be level with the hull bottom, switched to duct tape and it works, he thing flies about an inch high. I'll have a vid of the 2nd test up soon.

This thing was just a rough test rig, i just eyeballed it and quickly shoved some gear in it.
I can build one half the weight if i used sensible materials and make it fly even better with some fins. By the end of the 2nd test the EDF was duct taped on and the rudder was flopping in the breeze, i just wanted to see the hull lift the craft. It does, and on 2s easily. I'll go to 3s and maybe build another with twin lift fans front and rear, counter-rotating and using plenum air like yours for thrust.

Fun stuff, thanks for posting the details!

Go for it great to see you having a go, I'm sure you could make a flying hybrid model without much trouble. Ive just been concentrating on a practical design for full scale, but theres really no limit with models.

Here's with the short tape,,,

Skirtless hovercraft second test (1 min 0 sec)

Okay, i've got this now.

My crude craft hovers level an inch or more high, and is completely torque corrected with vanes inside the curtain nozzle. Simple as can be, i jammed a few strips of coroplast at angles at the front and rear, counters the torque perfectly, you'd think it was gyrostabilized and all the air stays under the craft in the curtain Th next hull i build will have correction vanes incorporated into the design.

Also, a variable vane would be an awesome thing to have plugged into a heading hold gyro, it would lock it right into place.


I'll glue 'em in place in a little while.

Soon i'm going to try cranking this thing up to 3s and find out what it's really capable of. The EDF is really supposed to be a 3-4s unit, 2s doesn't really give it much thrust, but even a little is enough to move a ground clearing craft. I'll have to change to a smaller prop and see if i can get away with the larger duct.

Also, i feel like i've perfected the easiest skirt to build, ever. There's no excuse for not having a hovercraft. The simple wall skirt is a length of duct tape a couple inches longer than the skirt section. I hold it out in front of me, sticky side away, and with my fingers on either end i make a fold to stick 1/3 of it's width back to itself. I use my lips to pinch the center to tack longer pieces together, then just run the duct tape back and forth over your chest/stomach or something rounded to pull it all together. Make 4 of these and use the 1/3 sticky part to attach it to the craft's hull.

My next step is to fold the duct tape over a piece of weedeater line to give it more structure and rigidity for a role as the skirtless craft's perimeter nozzle.

Im keen to see what solutions you come up with at higher speeds. -especially turning sharply without flipping. Ive tried winglets and various different concepts but nothing really worked properly, only for wide gentle turns. Over water you can use retractable fins but not sure if thats the right approach?
Don't know why this forums so quiet, I'm sure theres a lot of interest in hovercraft.

To keep the craft from flipping, you want something like a delta or V wing providing downforce. I put a swept V-wing KFm4 on one of my singles, up front, with a negative AOA and it tamed the flip quite a bit. Later on i went to twin swept fins leaning inwards at 45* and toed in at about 15* each. I mounted them up front and could toss into nearly any turn with the single fan racing class craft.

On later craft i dealt with the issue with a rear wing at positive AOA, lifting the rear of the craft instead of lowering the front, and just didn't turn faster than the craft could handle. Better piloting skills solved most of the problem. If i needed to turn, i'd start early, rotate slowly, and manage the controls to keep the outside edge of the craft up, but balanced, just like full scale F1 racers do. Bank the craft enough that it uses the ram air underneath to bank and turn the craft.

Especially with the weightshift craft i built, if i wanted to lift the outer side in a turn i lean inward, but if i want to set up for a sharper hairpin by tossing sideways, i'd weight shift to the outside and let it drift a bit, using the side of the craft as airbrakes, and then leaning inside when i want to tighten the turn. Weightshift side to side is on the rudder stick so it's just like flying a plane or a heli and doing either a coordinated turn, slip, or skid.

Also, ever notice how most craft flip more easily in one direction than the other? Gyroscopic forces. Tossing any hovercraft with a non-horizontal fan will impart a force at a plane perpendicular to that of the rotation. Turn left and the force will be applied downward on the left rear corner, making the right front of the craft lift. Turn the other way and it plants the right side nose while lifting the left rear. If you're racing an oval course, it's a simple matter of using a CCW prop to take advantage of the gyroscopic force to go fast and turn left.

Same thing with everything else, turn an rc car or boat too fast and it'll flip too. To prevent it, don't do that, hehe!

I don't know if there's much interest, i've searched everywhere and there's just not much out there. There's an RC hovercraft site/forum out there, they're the top result, but most of the recent posts are from years ago.

http://rc-hovercrafts.com/forum/index.php

Kinda sad, since they're the cheapest, easiest thing you can build and reward with great, reliable performance, and a ton of fun. It's a piece of foam with a hole in it and some duct tape in it's simplest form, Anyone who can cut a circle in foam can build one.

Originally Posted by Rusty Mustard

It's a piece of foam with a hole in it and some duct tape in it's simplest form, Anyone who can cut a circle in foam can build one.

Funny you should say that as I haven't been able to cut good holes in foam so far, I'm sure there's some very obvious way of doing it, but it's so obvious nobody bothers posting how to do it and it seems silly to ask!

(Seriously. I want to cut a hole for a 6" prop in a sheet of Depron. Doing it freehand always seems to go wrong and I don't have anything of the right size to use as a guide. Ended up using square ducts on the crafts I've built since they're easy and don't seem to leak much air).

Anyway I have been watching these threads as I find the peripheral jet crafts really interesting, they fascinate me in the same way ground effect vehicles do, everyone has seen planes flying high or a hovercraft skimming just above the ground, but to get something visibly hovering up high as if by magic looks so sweet.

My own work on skirtless craft so far has been rather interesting. The normal skirtless design (ie walled pressure chamber) is usually said to be limited strictly to the smoothest of surfaces, what I found is that if you overpower it to the point just below where it wants to lift off completely, you can get it running over surprisingly rough surfaces. Grass, gravel, potholed concrete, water...it ain't graceful and often grinds/catches, but it is fun. Managed about 15mm lift so far which can get you surprisingly far. Peripheral jet design from post #4 is next on my build list but it may be a while. I'm in a building drought at the moment, I have the time but have been almost paralysed because of all the projects I've got going at once, difficult to sit down and work on one where there's 6 others needing work at the same time. It's a busy time, starting a new job soon as well, tends to result in loads of half-finished not quite working fully projects lying around.

I don't know if there's much interest, i've searched everywhere and there's just not much out there

Yeah it's rather sad to me how inactive this section is. I've found myself drifting away from the plane and multirotor forums recently due to how repetitive the topics seem to be. Same old foamboard and 250 quad builds, you'd think there wasn't anything else happening in the entire RC world except for FPV racing right now. I get that it's new and cutting edge and I'm going to get into it myself at some point, but still, as I said the discussions about other multirotor experiments/builds end up pushed back several pages.

Speaking of FPV racing...it's a shame we're all so spread out across the world, because I'd love nothing more than to get together at some swampy bit of land with a bunch of amped-up hovercraft/WIGs and do some epic low flying racing

We can but dream....

Fifty, holes in foam are stupid simple, you need a 6" prop to fit? Make a 3" loop of string and use a sharpie and a nail inside the loop. Blammo! 6" circle. Now just cut it out with a sharp snapblade and you're there.


I might make a video of a simple hovercraft build and i'll show a technique anyone can employ for a great flying craft.

Okay, i built a new craft and made a video, i'll have it up soon, i'm editing it down now.

Here's part 1, the link to part 2 is in the description of the video.

How to build an RC Hovercraft Part 1 (15 min 0 sec)

As i post this the vid is still processing on YT, so if it's not up yet, check back.

Originally Posted by Rusty Mustard

I don't know if there's much interest, i've searched everywhere and there's just not much out there.

Kinda sad, since they're the cheapest, easiest thing you can build and reward with great, reliable performance, and a ton of fun. It's a piece of foam with a hole in it and some duct tape in it's simplest form, Anyone who can cut a circle in foam can build one.

The MHA in the UK is very active, our members attend various shows through the year and we have our own club meetings (last weekend we ran our models at an indoor RC racetrack for example and one of our members has fitted FPV on his craft). Check out our Facebook page (just search Model Hovercraft Association). There is quite a lot of interest in places like India too if you hunt around, and I recently saw a video on YouTube of a model hovercraft competition for schools in Iran, so I think it is a bit disingenuous to say that there isn't much interest.

I don't do facebook, so i'll miss it if it's on there.

That's cool you guys got a hovercraft club, but you're the only one i've come across so far. If there' really was some interest there'd be more than one club or a forum that has seen posts within the last year or two though. It'd be a lot more fun.

Do you guys hold races? This summer i'm trying to get some hovercraft racing going locally.

Yes we do races, though generally informal ones and no specific classes - typically the power of the machine is irrelevant when racing around a course as it mostly comes down to the skill of the pilot! Good luck with your endeavour, hope you manage to drum up some interest. We ran a competition to design a simple craft that a child could make to try to make it more accessible, and the winning design is very successful as it is robust, light and fast. You might want to try something similar to spark interest. But I fear we are going off topic (my apologies).

On the subject of skirtless craft handling, I wonder if the addition of puff ports in the form of mini EDFs would help with tighter cornering if they were programmed carefully with perhaps the use of a gyro. Just a thought.

I watched some of the MHA vids on YT this morning and seen the track videos.

Do you guys have problems with handling or stability? The craft in the vids seem to not be responsive or precise, my skirted single fan racing craft would eat that course alive. My racing class will be single fan, single servo models.

I bet a weightshift would work well on a skirtless craft for tightening up turns, it makes a difference on my skirted craft, and the skirtless ones are way more sensitive, a bit of bank would probably help it out.