Dave McD's
Ultra Sport 40 ARF
Kit:
Great Planes Take it waaaaay up, kill the engine, then dive it straight down. Listen to the whistling air noise as you do a high speed low level dead stick loop! Now make a full 360 degree turn to bleed off all of that speed. Wait until it's right in front of you and about 1 foot off the ground.....THEN lower the gear! COOL!!!!
I think that the Ultra Sport 40 ARF kit is a pretty good one.....for an ARF. The flying characteristics are more along the lines of a pattern plane than a sport plane. It definitely flys well! I've been VERY pleased with the way my US 40 ARF flys, and also how it's withstood over 7 years of active flying.
The landing gear mounting design is not the best in the world. Because of the ARF design that uses foamboard to wrap around the spars and ribs, there is no solid leading edge or sheeting to anchor the gear mounting structure to. The landing gear mount is simply glued to two plywood ribs that stick out of the spars. The wrap-around foamboard doesn't provide much structural support to the ribs or mounting plate at all. If you consistently make good landings, the gear mounting structure won't be a problem. It's weak, but it works. I really don't know how to correct this problem due to the construction method and the materials used.
The US 40 ARF is a really good airplane......except for 2 things. On mine, the firewall came loose after only about 50 flights, so I had to do some surgery and re-glue it. (what *IS* that $#!+??? Hot Glue?!?!?) But probably the worst problem is with the landing gear mounting design itself. It's just barely adequate to do the job. In fact, one of my gear mounts fractured when I happened to hit a "mole track" just as I was touching down on the grass runway. With a well designed landing gear mounting system, my plane might have bounced back into the air a little, but I seriously doubt that it would have broken the gear mount.
Despite the problems, it's still one of the better ARFs
out there, and it flys great!
The Hobbico Retracts:
I know that the Hobbico's have gotten some really bad press in the newsgroup, but personally, I haven't had ANY problems with mine. They worked perfectly when they were new about seven years ago......and they still work perfectly today, with well over 300 flights on them.......and all on a grass runway. They have never failed to retract or extend......and more importantly.....they have never collapsed during a takeoff or a landing. The only exception to this is when I waited too long to lower them. But that was MY fault.....not the Hobbico's fault.
The mechanical locking mechanism allows the gear legs to move side to side a little. It makes my US 40 look goofy when it moves side to side, but it hasn't caused any real problems.
The Hobbico retracts are well worth $20......good for $25......but I'd have to think about buying them for $30. And I probably wouldn't use them on a plane bigger or heavier than the Ultra Sport 40.
Poor landings will tear up ANY retract, but I'll admit, that poor landings will probably tear up the Hobbico retracts faster. They are definitely not as sturdy as my Rhom-Air retracts. On the other hand, they only cost a small fraction of what the Rhom-Air retracts sold for.
If you are consistently making fairly decent landings, then I see no reason that the Hobbicos won't work reliably for you too. If your landings could use some improving, then the Hobbico's might not be your best choice.
But if you choose to get the Ultra Sport 40 ARF, and your landings aren't consistently good, then the landing gear mounting structure in the wing will fail long before your Hobbico's will fail. Even the best retracts that you can buy won't make up for that weak landing gear mounting structure on the US 40 ARF.
Futaba S-148 Retract Servo
I couldn't bring myself to spend $50 for a retract
servo, so I modified a Futaba S-148 to travel 180 degrees, and used it to operate the
Hobbico landing gear.
The modified 180 degree Futaba S-148 has plenty of power to run the
Hobbico retracts, and it continues to work perfectly to this day.
For a list of step-by-step instructions on how to easily
modify a
Futaba S-148 servo into a fully proportional 180 degree servo,
click here:
S-148 Retract
Bottom line?
The Ultra Sport 40 ARF is an EXCELLENT flyer......especially with a 61 in
the nose. The weight and performance of the US 40 ARF are almost identical to the
built up version of the US 40. The main advantage of the built up kit, is that the
landing gear mounting system is much better than in the ARF version. Overall,
despite some minor problems, the Ultra Sport 40 ARF is still one of the best ARF planes
that I've ever flown or seen. If you get one, you'll love it!
Comments?
E-Mail me at:
dmcdnld@yhti.net