df engine and fan unit upgrade
 

I seen a guy with a hotboodies a-7 on ebay with a 25 size df engine and a different fan unit installed in the a-7, I am looking for something that will give the a-7 better take off and climb out, I have alot of trees at my found annd when you take off with any plane at my field you have to climb pretty quick, so do you guys have any idea what I could replace the toki 18 and stock fan unit...thanks

RE: df engine and fan unit upgrade
 

You can always try to locate one of the Kress .25 sized fans but I'm not sure how well it will fit in the A7. I was surprised at the size of the A7 the first time I saw it so there may be enough room in it for the Kress fan. Just curious, but did you ever try to contact the owner of the model you saw to ask him what he installed in the model? As for .25 engines, there are a bunch of K&B 3.5's and OS .25 VFDF's out there I'm sure you could locate by searching a bit.

John

RE: df engine and fan unit upgrade
 

for best climb out...

ESTES D or E series engines

RE: df engine and fan unit upgrade
 

What do you mean use a rocket engine on it,,,,,,,,?????????

RE: df engine and fan unit upgrade
 

That's called JTO (Jet assisted TakeOff! LOL)[sm=cool.gif]

RE: df engine and fan unit upgrade
 

JATO
http://bornholm.adsl.dk/modelfly/files/misc/c130-c.jpg

SJ.

RE: df engine and fan unit upgrade
 

Yeah, thats what I said I just missed the "A" if you read it I got the wording right.[:'(]

RE: df engine and fan unit upgrade
 

If all you need is some assistance on take off consider a bungee cord like the ones used for gliders. We use it for out electric DFs and they get up and go in less than 30 ft. Save your power for flying, afterall the navy use catapults too, ;)

RE: df engine and fan unit upgrade
 

how would you set one up and leave the landing gears on to.....

RE: df engine and fan unit upgrade
 

I've just put a picco 45 with Kress rk-740 fan in my HB A7. Only minor mods so far to get the unit in. Will be sooooo much better than before!!!!

D

RE: df engine and fan unit upgrade
 

Dave,

have you flight tested this new setup ? not too heavy ?

RE: df engine and fan unit upgrade
 

no, not yet.
The plane weighed 4.5lbs with the toki engine, this combo is light, and will produce 7lbs of thrust. I estimate dry weight to be just under 6lbs.

What do you think?

RE: df engine and fan unit upgrade
 

I'm no expert in the df area, but i would have a close look at the wing loading... I think the plane will be completely different : looooooong take offs, high speed landings, ... but higher top speed :D, obviously... You could perhaps add flaps ?

RE: df engine and fan unit upgrade
 

Keep us posted man, im very interested in this setup you got goin.

Luis

RE: df engine and fan unit upgrade
 

I upgraded my hb a-7 with the same set-up,,,,It added about 50 ft.more runway...for lift off,,,,I had to use flaprons to land it, it came in fast,, It did add I would estimate 20mph top speed staight and level,,,,It also improved on loops and rolls, I always had to go in a slight dive to do a loop......It it also sucks the hell out of fuel..........

RE: df engine and fan unit upgrade
 

I've got falps set up already. Anything for extra speed at the end of it!!!!

RE: df engine and fan unit upgrade
 

Fits nicely. sold my toki engine/fan combo for £80 (approx. $120)

Will be running the picco with a Weston uk, Genesis mini pipe.

Will be awhile before it's flying though, 1st thing to sort is how to install the unit, and lock it down? any ideas?????


dave

RE: df engine and fan unit upgrade
 

"I upgraded my hb a-7 with the same set-up,,,,It added about 50 ft.more runway...for lift off,,,,I had to use flaprons to land it, it came in fast,, It did add I would estimate 20mph top speed staight and level,,,,It also improved on loops and rolls, I always had to go in a slight dive to do a loop......It it also sucks the hell out of fuel.........."


Do you have any set up/fanengine installation photos? how did you screw the unit in there?

RE: df engine and fan unit upgrade
 

I see two ways to attach it :

1. the same way turbines are attached to the fuse ;

2. build plywood formers ;
glue 3 or 4 plastic parts to the fan shroud, with holes in them
attach the fan shroud to the plywood former with nuts and bolts

^_^

RE: df engine and fan unit upgrade
 

Yeah, thats basically the only things i could think of. I think the turbine method might be easier.
How would i go about that?
any links to pages that sell turbine straps etc..............

Cheers
Dave

RE: df engine and fan unit upgrade
 

the rk720 will give 7 lb with a hyper 21.

also, is that the kress shell that came with the kit?

the CF one?...i thought it was clear poly...?

and where's the carb, spinner and head shroud?....i'm confused.

RE: df engine and fan unit upgrade
 

No the CF shroud is an upgrade. carb is at back. Spinner is on order form kress, and have all the other bits here.

This is the rk-740 fan.

RE: df engine and fan unit upgrade
 

Can anyone help me figure out where to put the fuel tank? I have the option of the kress "internal" tank which sits in the fan shoud behind the engine, or a larger tank in the usual hotbodies A7 place.

the thing i'm worried about is balancing plane, I suppose as long as the balance point (dry) is the same as the original 200mm back from the leading edge things should be ok with full tank, half tank and almost empty??????

I would prefer to keep the fuel tank up top. (see pic)

RE: df engine and fan unit upgrade
 

Hi propbuster5532,
What size tank did you have in there? and where was it placed?

RE: df engine and fan unit upgrade
 

WoW. Looks like you got a big enough tank in that plane :)