RC India

With rain clouds hovering overhead, plane build is out. But keeping the spirit of the Sweepstakes was thinking of building something. So trying my hand on an airboat. Have no idea about the desirable dimensions,weight and power setup. So just drew a profile of an airboat and starting the build with foam board. And yes, the newspaper photo with the drawn profile

Ahaa! Look on the net for Gator Bait, an article I read about 20-30 years ago.

It's an ELAASTA! Extra Low Altitude All Smooth Terrain Aircraft  :rofl:

Not your typical Gas Guzzling 2 Dimensional bumparoo :D

Did a quick search, here are some results:

http://www.martysrcboats.com/air2.htm

https://www.youtube.com/watch?v=ENwmZsrfXA8 (https://www.youtube.com/watch?v=ENwmZsrfXA8)

As you can see, you have to wear a baseball cap and dark glasses to operate it  ;) :giggle: :giggle:

I'm sure, knowing you, this will be something really creative and am looking forward to following this build. (Also fits in well with what you said about flooded flying fields  ;) ;) )

Thanks Sanjay ji. My first try should be quite basic to see if it works.

Started build today. Drew the side panel and cut out 4 pieces from 3mm foamboard. Cut anothe piece 12in * 27in to serve as the bottom skin of the hull. The pieces were glued today to yield the hull of the airboat.

 Sir what are the basic proportions that you are using?
Making an airboat too for sweepstakes ;D

Your design and build looks nice sir :thumbsup:

@RCNeil21 - This is NOT based on any plan, so do not know how it will work out in the end. The distance berween bow and stern is 27inches, the beam is 12inches. Height of the side panels is 3inches. The motor mount is 9 inches from the stern and height from deck to motor shaft is 4 1/2 inches.  Will try to get a 3 bladed prop, if  I can locate one with the LHS.

I have also cutout the bulkheads for inserting a plastic watertight box for the electronics.

Today I prepared two rudders using a scrap piece of 2mm coro (packing of a parcel I had received). To strengthen the material, I glued 3 sheets and added bamboo skewers. I used a cycle spoke as a hinge for the rudders. The two rudders were connected together as shown.

Just occurred to me... Where will you put the batteries? Will the box be big enough for ESC & Batteries?

Yep. The box is big enough for the battery, esc, receiver and vill still have space to spare.

Deck covered and servo installed. Prepared a lip around the servo and radio box to prevent water from entering. Will be covered by a lid later.

Completed covering the deck. Installed a working rudder stick. Next prepared covers for the three hatches. To add scale features to the Everglades boat, prepared seats for the pilot(?) and the tourists. The seats were affixed on the three hatch overs so that the internals remain accesible even after the seats are in place.

More pictures of the build

Wow!

In the next set of pics we expect seat belts with quick release buckles...

Detailed looks of the seat.
beautiful build sir.

Ashok-ji; you are an artist!  :salute:

BTWI hope you glued the 3 rudder corro sheets with the flutes at 90 degrees to each other. That way it will have strength in both axes

beautiful  :thumbsup: :thumbsup: :thumbsup:

Thanks Iyer, Manoj, Sanjay ji and Col.
Yes, The flutes were rotated at each layer.

Very neat build. Love the seats

Great Detailing Sir! Sir you could also add a search light controlled by a knob on the TX :thumbsup:

Absolutely LOVE the detailing. Inspiring work Sir.

@ashok baijal,
VC is the guy who has the most posts on this forum (excl Anwar)
He's been strangely quiet for the last six months or so.
I think nowadays he responds only when something truly impresses him.

Thanks VC. You should also be building one excellent model for the sweepstakes and share your techniques with all of us specially the embellishments you make for your boats.

@Iyer.I am rather slow at finishing the two models under construction for reasons you know. I tried the new epoxy I got from Mumbai for fibreglassing the boat. It was a complete disaster and I had to scrape off the fibreglass with some residual damage to the boat. Now I have more work to do for finishing the boat.

I need a 30/40 amp ESC on loan for the trial as getting a new one from HK will take time. I thought that I had one lying somewhere but I was wrong.

@Iyer. Recd the ESC in today's mail. Thanks.Will send it back once I get mine.

After a break, started fibreglassing the hull. My earlier attempt to use a new epoxy that I got from Mumbai was a total fiasco as it refused to stick properly to the pvc foamboard. Had to scrape it off and the red marks seen in the picture below are spots left by this epoxy. So now one kg of epoxy down the drain!  >:(

I have started fiberglassing using Araldite and covered one strip today to see how it sticks to foamboard before covering the remaining hull.

Progress as on 16-7-15:
Fiberglassing of hull completed. Next step is deep sanding and a coat of NCPutty.

A coat of ncputty applied and sanded. Next would be a touchup with the putty on areas which are still rough.

I need advice on the paint to be used. Can fevicryl paint be used on an air boat or regular thinner based paint has to be used? Further can regular thinner based paint be sprayed using an airbrush or will it get clogged? Any suggestions for a colour scheme?

That's coming out real Nice sir.

How I wish I had one such boat in Jalandhar to try here.

(https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xat1/v/t1.0-9/11329787_485078478335405_8519942047195069150_n.jpg?oh=4fc26124394f62d27e50d902fe90aca6&oe=561878A1&__gda__=1448311678_b3b37c21283f76728e09e22f9ccc2581)

@Sundram.
Col I need your advice on a suitable paint for the boat. I would like to inaugurate my airbrush

As there is no fuel, go ahead and use auto refinish paint (NC Paint)

Keep good visibility in your colours: though boats generally don't go as far away as planes, water spray makes white difficult to see

Since it is going to be used on water I would suggest Automotive Urethanes / NC Lacquers to make paint water safe which can both be used in airbrush with thinner.

Care however should be taken to clean and rinse airbrush thoroughly immediately after use with thinner.

I would have recommended one more cheaper alternative of Craft fevicryl Ceramic Paints which also makes a hard water proof coat but only after a heat treatment with a heat gun. Since you have used Foam inside the structure before glassing I would not recommend it now. Fabric Acrylics are also not recommended for the same reason of requirement of heat treatment to make it water proof.

If use of airbrush is not compulsory I would recommend automotive paint spray cans available readily in all colours, even in metallic colours now a days for Rs 120-150 a can. which is a no fuss easy to use in this case. you may need not more than a can or a colour each to maintain the colour scheme.

All the best sir.

After fibreglassing the hull gave a base coat of white paint. Bought two spray cans of yellow and red for final coat. Waiting for base coat to dry - next some filling of irregular spots, sanding and then final painting. And then, a taste of water.

My son had come today and wanted to try his hand at the boat. So the maiden was done today.his first attempt video. Camera managed by my wife. Only a small part of the run was captured.

https://youtu.be/2w2WjT1WBFI

Very nice  :thumbsup:

Now for the next video - turn on the juice  >:D

Awesome Sir.  {:)} {:)}  Cut some stencils and go for some crazy Graphics and Colour schemes.  :thumbsup:

PS: keel lines on the belly would have been great to maintain directional stability. May be five lines of Bamboo Kebab Skewers epoxied on the belly and sanded on the sides to give the lines on the belly would have done the trick.

Thanks Sanjayji and Col. I had thought of putting the keel lines but wanted to try it out before adding them. Will try to add them this week as final painting is still to be done. Scratching my head for a design.

Second Day - Short Clips

https://youtu.be/k5hW9_pbSIQ

https://www.youtube.com/watch?v=ONNPM5c5oo0

@ashok baijal,

An air craft to beat the rain!

Wondering about the following (besides paint scheme)
1. How deep does she ride?
2. Is the waterline parallel to the keel/deck? Should it be? Should she ride a bit nose up?
3. Will she nose down on full power?
4. What should be the attitude at low speed / high speed? Same? Different?
5. What's the relationship between the CG position and motor thrust line.
6. Is a small water rudder desirable? Should it be pivoted at the top, to provide full surface at low speed and less at high speed

Much easier to ask instead of doing the research myself  ;D

Super Nice  :thumbsup:  {:)} {:)}

@ Iyer
Your questions - my responses
1. How deep does she ride?  About 1.5cm  Weight 2470 gms, width 31cm, length under water 59cm full length of boat 70cms
2. Is the waterline parallel to the keel/deck? Should it be? Should she ride a bit nose up? It is parallel. Battery can be shifted aft. Can be tried, but as of now she sits and runs parallel to the deck
3. Will she nose down on full power? No, she does not.
4. What should be the attitude at low speed / high speed? Same? Different? The attitude remains the same other than it creating a nice wave at the bow at higher speeds. You can clearly see water rising about 3cm at the bow.
5. What's the relationship between the CG position and motor thrust line. Do you mean that the thrust line should point a bit upwards so that the bow rises at higher power? Yes, this can easily be done by putting a few washers on the upper motor mounts. P
6. Is a small water rudder desirable? Should it be pivoted at the top, to provide full surface at low speed and less at high speed? The turns are smooth and no issue. I did not run it at full power as I was using a 25amp esc and because it was not placed in an open place it was prudent to run at half power to avoid a brownout in the middle of the lake. Will soon be replacing the esc with a car esc with reverse capability for ease in manuverability and heat management as they are supposed to work away from direct airflow.

BTW need your postal address for returning your ESC.

A coat of paint

Super Sir. That's a beauty.

Thanks Col. Wife has consented to make two dolls for the driver/pilot (?) and one passenger  ;D

Wow.
Even has non-slip floor mats!

....wow ! I thought this was still WIP. Very nice run  and so easy to turn....the waves look neat too  ;D

Edit: have you tried it at WOT, or is at WOT already?

Thanks Iyer and Bmblb. By the way what is WOT? Recently I have installed a car ESC as it has a small cooling fan and can move forward and reverse. I have still to go out to the lake to test the new setup. Will update once I go.

Edit. The throttle was around 50% most of the time.

WOT- Wide Open Throttle