arcdude

No, not like the Swamp buggy, rather more like a profile plane. This is a prototype and the basic unit in the pic is 1/2" ply in a single stand whereas the normal is a box type and everything will be mounted directly into it. I'm considering water proof servo's which will be mounted in it as well as a waterproof container for the receiver. The engine plate pictured is adjustable for thrust line and all that is needed is a different plate for whatever engine I choose which is usually a 61 pictured or a 46 TT. The module will bolt directly onto any base design I choose and in literally 1 hr I can swap it back and forth. The design I have can easily be adapted to a single or double rudder. The tank is mounted with elastics to prevent foaming. I figured when designing these boats the greatest amount of time is spent on the engine module itself so I decided to make something that can be adapted to any base boat desired instead or re-creating the wheel every time.

A dremel tool I found to be an asset in getting rid of the nasty glue line prior to sanding the remaining foam down, better one slight dip in the center than two valley's one on each side of the glue line.

MarkPrima

1QwkSport2.5r - wow your airboat runs well on grass! The 4-stroke has such a nice sound to it. Was there any major scuffs on the underside from running on grass?

MarkPrima

arcdude - thanks for the advice on the glue - I worked at it last night. I'll post some photos today.

Very slick design on your motor mount!!

1QwkSport2.5r

No there wasn't any scuffs on it. It was coated with 3 coats of epoxy, then sanded and fiberglassed later, and I use a topcoat of waterbaser polyurethane on top because it dries incredibly slippery. That boat weighs like 8-9# and the engine is a 20cc Enya. That was my very first build actually.

MarkPrima

Very good!

Here is the start of hull shaping, I recessed the stern area for the motor mount. I am thinking my motor mount is over-kill and too big, I'll post a pic after the paint dries on it.

one up-side-down - Darn iPhone

1QwkSport2.5r

Looks good so far. Autocorrect nailed me with "water weed" poly instead of "waterbased" poly. Damn iPhone! LoL.

MarkPrima

Thanks for that update - I was wondering what that was.

Here are a few shots on what I did this weekend.
I lined the interior of the RX opening in 1/16" ply - I made a hole for the RX battery to be inserted and lined with foam.

I still have to design the bow scoop.
The motor mount is huge, but I'll see what happens

MarkPrima

I had the same problem when I had to laminate balsa to make the fuselage for the Telemaster.

How do you guys with airboats do RX switches? On the planes I use a simple switch to turn off RX.
OR do you just remove a cover and turn the RX off?

I'd like to make an airboat with ribs and plywood but with the Canadian dollar at the current level I will see what happens - most of our hobby stuff is shipped accross the river and we simply go pick it up.
Yesterday I did get a sheet of 1/8" Baltic Birch plywood from our local specialty lumber store, but the 1/16" will be a problem.

arcdude

Good day Mark,

For the switch I simply use an rc push pull sw through the lid or side of the radio box and put a dab of car wax around the metal rod or vaseline where it goes into the plastic, I've never had a leak yet. A good safety measure that is used by many is to put a tampon, yes a tampon under your receiver, top notch backup in case of a leak.


For your wood build I suggest 1/8 lite ply for airplanes for the ribs or as I mentioned earlier a door skin from home depot, it's a lot cheaper and an effective alternative.

The boat above looks like it's coming along quite nicely, is the bottom angled or just a gradual slope to the front?

MarkPrima

Thanks arcdude for the info about the switch, I just made an order but I'll put that on the list for my second order. Clever about the tampon, we use something similar in the lab when making solutions, I'll have to raid the lab and get some.

About the plywood, I have 1/8" ply to construct the ribbing, but I think I'll have to break down and order 1/16" ply from the States.
You mention:
Would it be something like this?

Yesterday my Proxxon table saw arrived, I have the Proxxon scroll saw but now I can do nice straight cuts with the table saw

Yes the bottom is tapered up to the bow, I'll have to take a proflie shot.

I worked on embedding stock for the motor mount, then I'll make two bolts go right through the foam to the bottom, reinforced with stock.




One piece embedded, the Dremmel tool really comes in handy.

arcdude

The ply you showed in the link looks like some kind of hard board, if it is, it's heavy stuff. What I'm talking about is 1/8" or less and is 3 layered mahogany, the only draw back to it is it splinters easy so watch your hands on the edges. Or you could order yourself a sheet of lite ply for airplanes, I don't recall off hand how expensive it is, certainly cheaper than the birch ply.

If you have the router base for the dremel it comes in handy for doing the slots for embedded parts.

1QwkSport2.5r

Mahogany is heavy. If you're just using the 1/8" ply for the framework/ribbing, then use the lightest stuff you can. I use balsa most of the time - in fact all of my boats' inner frames are balsa except for the SI3 boats. If you can't get 1/8" balsa, try to find liteply as Arcdude suggested. You'll want to use solid birch plywood or a light solid hardwood to embed for mounting the engine stand and such. Try these guys; I use their stuff all the time. http://budnosenmodels.com

arcdude

If you were around in the 70's you'll recall the mahogany doors that were the mainstay at the time, the skins were 2.5 mm, and the entire door could be carried by literally two fingers. It is becoming a little hard to find nowadays and has been replaced by a sheeting called Luan plywood which is just as effective in it's use for our purposes. What you need is light ply that is 1/8" or less and 3 ply, there is other types including poplar. The alternate plywood's are much cheaper than the lite ply used in rc aircraft, you'll just have to invest a little time in phone calls and checking local supplier's.

Here is a pic of a piece of Mahogany door skin that measures 6.5" x 16 x 2.5 mm thick and weighs 3 oz, pretty light I think.


Here is one link to luan plywood, most lumber yards do carry this or something similar. http://www.menards.com/main/building...-external-mcom

1QwkSport2.5r

Most of that luan plywood is mahogany anyway - including the cheap line of hollow core doors. The cheap Menards doors usually have white mahogany instead of brown mahogany which is what was commonly used on those 1970s homes. Liteply is darn near as light as balsa. I'd pay a little extra for real liteply if it was available.