Topic: air boat fast build (Read 37844 times)

triumphjon · « **Reply #75 on:** April 12, 2011, 11:42:08 pm »

i wasnt going to fit a cage , there are no other models operating at the same site , no h&s to deal with either ! my current battery packs are all standard 7.2 volt nimh tamiya style units . is it better to position the pack towards the aft , or midships ?

The long Build · « **Reply #76 on:** April 13, 2011, 12:07:50 am »

With a heavier battery I would say aft slightly, and to be honest the cage is more cosmetic than protection

triumphjon · « **Reply #77 on:** April 13, 2011, 08:46:40 am »

thank you , it was towards the aft i was thinking of , but its always good to hear from somebody who has already exeperimented !

LarryW · « **Reply #78 on:** April 13, 2011, 09:28:18 am »

HI ALL , i still say its the proping......LARRY

triumphjon · « **Reply #79 on:** April 13, 2011, 09:37:14 am »

what props have you tried larry ? im using a standard 6 volt graupner speed 400 motor , direct drive with a 7.2 volt battery , although similar in basic design to your hull ive made mine with a slight taper along the hull sides & an 1 inch chine as the hull changes from the sides to the bottom skin ! will post pics when ive taken them ! jon

LarryW · « **Reply #80 on:** April 13, 2011, 05:04:44 pm »

HI JON 5x6 and 5x3 reversed , try hunt down a pusher , will get one at south west show LARRY.,.

triumphjon · « **Reply #81 on:** April 13, 2011, 05:14:05 pm »

the one a local aero shop supplied is a perkins APC 7X6 propeller , after id told him what im planning to use it for with the motor & battery combination ! hull is almost ready for final sanding & sealing prior to being sprayed , hoping to be in use before easter this year !

triumphjon · « **Reply #82 on:** April 28, 2011, 10:40:57 pm »

having changed my prop for a 6x4 and coated the hull in polyester resin the performance is much better , however the steering is c p unless at full throttle ! has anybody else had this effect ?

Patrick Henry · « **Reply #83 on:** April 29, 2011, 11:40:41 am »

You guys seen this yet?
http://www.sussex-model-centre.co.uk/shopexd.asp?id=35077

Rich

Circlip · « **Reply #84 on:** April 29, 2011, 01:45:24 pm »

Quote

try hunt down a pusher

?????

  When you're standing behind the boat it's always a pusher.

  "Pushers" and "Pullers" only apply when strapped to an IC engine.

   You use a Standard "Puller" prop and reverse the battery connections for Electric. When veiwed from the front of the boat, a "Puller" always rotates anti-clockwise, unless a "Pusher" costs more money, then go figure?

Make sure if you buy a pusher propellor, you also fit it to a pusher motor.

  Regards Ian.

john44 · « **Reply #85 on:** April 29, 2011, 02:53:12 pm »

Quote from: U33 on April 29, 2011, 11:40:41 am

You guys seen this yet?
http://www.sussex-model-centre.co.uk/shopexd.asp?id=35077

Rich

Hi Guys,
I have made 3 airboat hulls very similar to this type of air-boat. Scrapped the first, gave the 2nd one away,which had a slight V
towards the transom to ease turning. I fitted it with a graupner 500 race motor and a 7x4 prop. quite impressive on the water.
I have since built a 3rd boat I have stepped the bottom of the hull to hopefully get it off the water quicker. I have fitted a brushless motor and a 8x6 prop I am going to run it on 8 cells.
Should be fun.

john

triumphjon · « **Reply #86 on:** April 29, 2011, 05:32:22 pm »

sounds interesting john , tis is my first build airboat , which ive added a slight chine , my second boat is under construction with a completley flat bottom made from yellow foam glasssed over with polyester resin ( for my step grandson ) ive been thinking of maybe a stepped dory hull would perform well ? my current water is a sheltered area of sea near to where i live !

Nige52 · « **Reply #87 on:** April 29, 2011, 07:02:09 pm »

There are some great designs floating about...sic. One of my favourites is Old Anarchy, VIDEO HERE
This guy designs his boats with angled sides so the skim the water and don't cut in and fall over. Unfortunately his website is down for new additions.
Cheers

tica · « **Reply #88 on:** May 04, 2011, 11:52:24 am »

I did a Skimmer last summer. It's build as GG's plan suggest, balsa covered with tissue and dope.

Motor: Speed 400 6V
Prop: 5.5"x4.5"
ESC: Robbe air control 819 Lipo.
Accu: 2S Lipo 1500mA.

Ready to sail (fly) Weight 490 grams, it goes like hell, but it's very hard to steer at full speed.

It's a great eye catcher at the lakeside especially here in Denmark as there are not that many who enjoy model boating.

triumphjon · « **Reply #89 on:** May 04, 2011, 03:41:54 pm »

i had the same problem with mine , overcome by making the rudder 85 mm x 130 mm !

The long Build · « **Reply #90 on:** May 04, 2011, 09:21:00 pm »

Quote from: tica on May 04, 2011, 11:52:24 am

I did a Skimmer last summer. It's build as GG's plan suggest, balsa covered with tissue and dope.

Motor: Speed 400 6V
Prop: 5.5"x4.5"
ESC: Robbe air control 819 Lipo.
Accu: 2S Lipo 1500mA.

Ready to sail (fly) Weight 490 grams, it goes like hell, but it's very hard to steer at full speed.

It's a great eye catcher at the lakeside especially here in Denmark as there are not that many who enjoy model boating.

Looks nice, would be good to see a video..

The long Build · « **Reply #91 on:** May 04, 2011, 09:24:49 pm »

Quote from: Circlip on April 29, 2011, 01:45:24 pm

?????

  When you're standing behind the boat it's always a pusher.

  "Pushers" and "Pullers" only apply when strapped to an IC engine.

   You use a Standard "Puller" prop and reverse the battery connections for Electric. When veiwed from the front of the boat, a "Puller" always rotates anti-clockwise, unless a "Pusher" costs more money, then go figure?

Make sure if you buy a pusher propellor, you also fit it to a pusher motor.

  Regards Ian.

Problem with that is that I have found when using a standard prop and reversing the motor the prop flexs more one way than the other as my engine mount can testify to.

knoby · « **Reply #92 on:** May 04, 2011, 09:51:30 pm »

Problem with that is that I have found when using a standard prop and reversing the motor the prop flexs more one way than the other as my engine mount can testify to.

surely you just turn the prop round & reverse the motor so the prop still pulls?? or am I missing something?

Glenn

The long Build · « **Reply #93 on:** May 04, 2011, 09:56:06 pm »

Don't know, I'm Confused now..

knoby · « **Reply #94 on:** May 04, 2011, 10:29:25 pm »

its hard to explain in words but i will give it a try.

if you are using a puller prop, the motor is behind the prop. Therefore the front of the prop is facing the front of the boat & the back of the prop is facing the motor. This is the way a puller prop works.

If you want to use this prop on a reward facing motor, you need to keep the front of the prop still facing the front of the boat in order for it to work correctly. Therefore the front of the prop will now be facing the motor.

Its so much easier to show than explain in words

Hope this helps, not confuses

Glenn

knoby · « **Reply #95 on:** May 04, 2011, 10:33:02 pm »

Should have added, you have to reverse the motor direction as you have turned the motor round, in order to still spin the prop in the same direction when viewed from rear of boat.

i wish i had never started this

triumphjon · « **Reply #96 on:** May 04, 2011, 10:37:24 pm »

by doing this you would need to modify the prop hub to sit on the adaptor ?

knoby · « **Reply #97 on:** May 04, 2011, 10:43:05 pm »

After reading this thread, thought I'd have a go myself at building 1 from the scrap box, so spent easter sunday & came up with mk1. made from 1.5 mm plastic card (cos thats what i had). Driven by a 2300kv brushless & 10 AA cells. Went ok, but the srtraight sides threw water up in to the prop on faster turns. This caused the boat to slow dramatically & dig in on the turns. Was fast in a straight line though, if a little tricky to steer in the high winds.

The picture is after I stole some parts to make the mk2 this weekend

knoby · « **Reply #98 on:** May 04, 2011, 10:45:22 pm »

Quote from: triumphjon on May 04, 2011, 10:37:24 pm

by doing this you would need to modify the prop hub to sit on the adaptor ?

Possibly,it depends on the prop & adaptor, mine fitted ok, just did it up FT!!

knoby · « **Reply #99 on:** May 04, 2011, 10:52:31 pm »

The mk2 was made this sunday, decided to use sloping sides & make it look a little more boat shaped. Also tried twin rudders to see what difference it made.

Took it out last night, but it was really windy & was impossible to keep in a straight line. there was only a tiny part of the lake sheltered from the wind, but it went well in the conditions. not water getting to the prop this time & it power slides beautifully. The AA cells got a little to hot for comfort though!! but I always knew i was pushing my luck using them.

flying debris hitting the prop brought things to an abrupt end, causing the prop to break, but will get it fixed for the weekend, will also get some lipo's for it.

Glenn

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Author Topic: air boat fast build (Read 37844 times)

triumphjon

The long Build

triumphjon

LarryW

triumphjon

LarryW

triumphjon

triumphjon

Patrick Henry

john44

triumphjon

Nige52

tica

triumphjon

The long Build

The long Build

knoby

The long Build

knoby

knoby

triumphjon

knoby

knoby

knoby