JamesDL

Hi All-

I'm planning to build a Great Planes BLT. I'm wondering if the power system that they recommend (T280 motor, 4.1:1 ratio, 10x4.7 prop, with a 1200mAh, 7 cell 8.4V, NiMH bat) is optimal for this plane. Is it possible/desirable to add more power or make it more efficient? Cost is not too much of a consideration or me, I'd rather get the best components to start out with than feel like I have to upgrade later.

I don't have any experience putting together a park flyer electric kit like this, but I've flown small electric park flyers before, and have built a lot of free flight kits (mostly Guillow's) and I am just finishing a Great Planes PT-40 nitro kit now, so I'm pretty confident that the BLT won't be hard for me.

One reason I want to build this kit is to get some experience with electric and micro-servos so that I can ultimately convert a Guillow's scale kit to full rc. That will probably be a year or two down the road however.

Thanks!
James

Time Pilot

I'm not sure what you mean by optimal. I flew my BLT with a system very close to recommended and it served me well for the time that I had it. It flew like a trainer.

The 1200mAh battery is too heavy, IMHO. Something around 650 mAh would be better.

I've written some things about the BLT here, which a search should uncover along with some newbie ramblings. [sm=red_smile.gif]

But unless GP updated the kit, the things that should be modified are:
1. the way the tail is constructed and glued to the fuse.
2. strengthening the pylon by gluing thin balsa cross grain.
3. using a harder wood to support the LG and have the LG face forward rather than straight down.
4. I had some problems with either the rudder or elevator clearing a surface. I carved some of the bits away, but I recall if it was built a bit different, the problem wouldn't have been one.

1. I'm about 50% sure one of my crashes was due to the tail coming unglued. I didn't trust the film to balsa joint when I built it but didn't trust my instincts as I was a new to the hobby.

2. Until I rebuilt the pylon, almost every crash, it broke along the grain.

3. The BLT will nose over easily with the LG straight down and will eventually cut into the balsa that is supposed to keep it pointing straight down. I used some small bits of popsicle sticks instead and angled the gear forward about 15%.

Other bits: If I were to build another, I'd consider using a thinner film than the clear Monokote. I didn't have any problems with warping the light structure while shrinking, but I could see it easily happening.

The nose will break too--another weak spot. When I redid the pylon, I rebuilt the plane so that the nose could easily be replaced by a stick 1 cm square if it broke.

I also had some problems with the way the BLT motor mount glues one stick over another. I reinforced with 2 bamboo dowels through both sticks.

If you want more details that a search doesn't uncover, let me know and I'll see if I can conjure those memories.

JamesDL

Time Pilot-

Thanks for your reply... I actually think I read some of your posts in the archives...

I got the idea that the nose is vulnerable and weak and I was thinking to modify it so that in a crash it will break in a way that is easily replaceable.

I realize that the power system is all about tradeoffs, but I was reading about the Fundango, for which everyone seems to agree that the original recommended configuration was simply all wrong. I guess I just want to make sure that is not the case with the BLT before I spend a lot of money on the components.

I'll check out more of your posts in the archives.

James

JamesDL

So I just ordered the BLT kit from tower with the manufacturer recommended power system, ESC, and flight pack. However, I got 2 650 mAh batteries instead of the 1200mAh to save weight.

I'm really excited to build and fly this thing, it looks like it shouldn't take me more than a week to build.

James