pooba

I have just built a spa3d and installed a K&B45 sportster but I cannot get this engine running reliable or smoothly at all. I have played with the needle valve, adjusted the idle thingy, replaced the glo plug and cleaned out the fuel tubing but still it cuts out when it goes up to full throttle and even when i do get it running semi ok, after 10 seconds or so on idle it cuts out when i move the stick up to full again. I also think the engine has a slightly bent shaft (about 3mm diff. at tips of 11"prop) and i got the engine ages ago second hand from this dodgey guy who always crashes his planes back when i knew not much stuff.

Anyway, i am going to get a new engine and am wondering which thunder tiger motor out of the gp42 and the pro46 is more suitable for my spa3d(weight without engine is about 3.74 pounds (about 1715grams)). (I want to get a TT engine 'cos a model shop here in New Zealand is selling them really cheap.)

What are peoples experience with these motors and is the extra weight of the pro46 worth it in terms of power and stuff compared to the 42. I would be happy with an engine that can hover my spa3d fine with enough power to pull out of a hover (doesn't need to shoot uplike a drag racer) and if the 42 can do this i will get that cos its only NZ$120 (about US$65)

thanks.
blythe.

FrankC29

for a spa3d, the pro46 most deffinately, you need the extra power to fly 3d proper. If you do decide to go with the 42 anyway, downsize the dimensions a bit, I believe the Spa3d instructions mention some suggested deminsions for different size engines. I think for .40's it's a 34" wing? I hear the .42 is great once you slap a mousse can pipe on it.

Madd_Maxx

pooba:

I have a spa3dt with a TT gp 42 on it swinging a 11x5 prop....it will hover but really doesn't have enough power to pull out with authority. The only difference is that my spa3dt weights in at roughly 4.5 - 4.7 pounds due to the tube fuse (it's roughly a pound heavier than your spa3d). If the 46 isn't much more in cost than the gp42 I would get the 46 for the small added performance you will gain.

I do need to get some video shot of the spa3dt with the old gp42 on it so you can see what it can do. That is if the weatherman would ever give me a break (it has been either raining or snowing here for the last few days) so I can enjoy a nice day flying.

Madd_Maxx

t4

My Feedback: (73)

pooba--

The 46 PRO BB is the way to go! Even if you add on weight (dual aileron servos, skis, floats, 3DT, etc.) the TT 46 exhibits enormous authority with a 12 x 4 APC prop.

--T

3d-aholic

My Feedback: (7)

I am building a spad3d-40 but haven't flown it yet....

But, it looks like my final weight putting all the parts on the scale is about 3.6 with the engine. But I did trim down the size of the U channel as well s the wing per the instructions. If that is my final weight, I feel confident the 40 will work but if it doesn't than I'll just have to buy bigger.

pooba

madd maxx - my spa3d is 3.74 pounds without the engine so will be about same weight as yours. I don't know how people can get these spa3ds under 4 pounds with engine! Maybe mine is so heavy because i am using 5mm corro (don't know where to get 4mm here) and i have used some wood inside the aluminium channel to strengthen it (my aluminium is not a U, its a L which is higher that the U so with the wood it might be rigid enough).

I have decided to get the TT pro46 and ordered it today

thanks everyone!

novabill

Good choice,

I think 2much said 3lb6oz without engine and I think anyone with 3-1/2 lb 36"WS and .46power spads has bunk scales. You are doing good @4.5lb

William

novabill

Sorry,

2much has engine on and bunk scales

AirIck

tt pro .46 squirts out of a hover unlimited w/ 12 1/4 x 3 3/4. frog hair over 4 lb

rlt55

The TT46Pro works real well on a 36"WS QHOR too.

3d-aholic

My Feedback: (7)

Maybe, I admit this is the scale I use to weigh myself which I'm sure is not calibrated to weigh things under 5 lbs....especially since this scale has been weighing me so close to Christmas time. Well off to put on my red suit....

{Keep in mind though that I am using 4mm coro, U/C channel not Tube, reduce U channel by 4 inches, using 34" wingspan, not using profile fuse, single aileron servo, modified lighter MW landing gear, using extra light wheels designed for electrics}

novabill

you are probably pretty close, but I have'nt seen one under 4 lb yet. I think it can be done though and I will do it, but it gets away from the cheap aspect.

William

3d-aholic

My Feedback: (7)

Actually I haven't accounted for the wrapping on the receiver, about 12 cable ties and other things....I expect to be closer to 3.8-3.9 on my scale when done. Also using my uncalibrated hands I believe my old fox 40 weighs less than an OS 46....come to think of it. I know it shouldn't but it felt that way.

If I have to buy a new engine I will, but I'm trying to give a home to this old guy for nostalgic sake.

Oh, and the stickers and labels and things...thats whats going to really kill me.

Dave McDonald

My Feedback: (19)

At 3.5 pounds dry, a 32" McDDD flys great with a TT 42GP....especially with a MCP.

But if your plane weighs over 3.5 pounds, I'd suggest using the TT Pro 46 with a 36" wingspan, which should get you close to about a 4.25 pound dry weight.

3d-aholic

My Feedback: (7)

My 3.8-3.9 is with the engine and the propeller and spinner for that matter.