It Flies!!!

[Chris]

Well, I got tired of waiting to build something nice (my Pitts is out of commission awaiting a new prop shaft for the gearbox thanks to a nose dive from about 15 feet, and I haven't had time to finish my plans for a Hawker Fury), so I whipped this thing together in about 3 hours. It's obviously based on the Thistle by Martin Gregorie. Mine has a 22 inch wing span, 3 inch chord and is powered by a KP-00. A SHR Hybrid receiver, 2 Wes-Tech servos and a 5 cell 50 mah pack completes the hardware.

Total weight is just shy of 2 ounces and it seems to fly fairly well. I've only been able to make short hops in my backyard, but it's able to climb nicely and turn in approximately 8 to 10 feet. I can only fly about 30 feet to one end of the yard, turn around and fly 1/2 way back, at which time I have to dive to the ground to avoid a potential landing in the pool. ;) Best of all, it seems amazingly crash proof. The first flight ended in a nose dive straight into the ground thanks to a reversed elevator servo. Other mishaps include a collision with a picnic table and a few flights into the woods where some trees ended all hopes of forward flight. Overall, I couldn't be happier.


http://www.rcmicroflight.com/upload/my_thistle.jpg

[pease1]

Wow! Nice thistle! Mine looked similar but with shorter wingspan. I never really got mine to fly - was too heavy with the GWS receiver and 6 cell battery. I always liked the look of the thistle! Congrats! how about some movies of flight?

[Chris]

Thanks Allen. I had to go with a longer wing because the chord was so small (all I had was 3 inch sheet balsa).

Yea, I always thought it was a cool looking plane. This one was really hacked together - no plans or anything, I just looked at yours and started building away.

I just had a few more flights and must say, it flies really well - nice and slow, 1/2 throttle is fine, full throttle for a second or two immediately reverses an oncoming stall, and I have to update my previous post - it'll turn in about 4 to 5 feet pretty easily. I'll definitely be building another one of these, maybe a little more refined and with the hardware more enclosed to improve aerodynamics.

I'll work on some videos. My digital camera doesn't have a movie mode, but a friends does... and he has a nice big yard! ;)

BTW, I've been following your Electric Mite conversation (with yourself ;)) with interest. I saw it a while back and always figured I'd build one some day, maybe a KP-00 powered MicroMite... ;)

[pease1]

Funny, the next step for me with the Electric mite is scaling it up for Speed 280 use :-)

I'm interested in your refined thistle project. I've always planned to go back to the thistle - it's too neat of a design not to.

I'm glad my thistle project got you interested. That's why I spend the time to make the web pages - to share and enjoy.

Keep us informed on your futue thistle progress,
Al

[BogusModem]

Nice! The Thistle got me interested in this hobby. :) Do you have good pics of the control surfaces? I just can't get them right...

[Chris]

Here's close-ups of the tail. I used very thin (probably 1/16 inch) strips of CA hinge to attach the control surfaces. The control horns are 1/16 spruce. Again, I really just slapped this thing together, so it's a bit rough. I had read that Allen's didn't fly too well and didn't want to invest a whole lot of time in something that might not fly.

Allen, too big and you won't be able to call your Mite a Mite... ;) That is funny, I've been in this mode where smaller is better (thanks to my cramped flying areas). I'll definitely keep posting with my Thistle progress.

http://www.rcmicroflight.com/upload/thistle_tail.jpg

[pease1]

My thistle's problem was using too heavy of a battery pack and too heavy wiring for everything. It was close. The other problem was I tried the maiden flight in too high of wind. How many cells did you use?

Al

[ 06-26-2001: Message edited by: Allan Wright ]

[james_a_moles]

What is the KP-00 gearing? If it's the 2.67:1, won't that burn out the little motor on 5 cells? Also, how long of flights are you getting with the 5 cell pack before the BEC kicks in--or did you disable it? Questions, questions, questions...sorry!


James

[Chris]

Allen, I'm using a 5 cell pack. And I wouldn't dare to fly mine in a breeze, much less a wind. A tiny breeze blew as I was traversing my back yard and it bobbed up and down like a cork in a stormy ocean.

James, it's the 4.75:1 KP-00. I was worried about burning it out, but it seems fine on 5 cells. It seems to run about the same speed on the 5 cells through the receiver/esc as it does directly on 3 cells. I still haven't been able to get to a proper flying field, so all I've been able to do are short 15 to 20 second flights, but I'd estimate 5 minute flights are possible.

[pease1]

I was trying to use the geared N-20 roadkill powerplant with a 9-volt NiMh 'transistor' battery or a 6-cell nicad pack. Like I said, it was a bit heavy. Maybe I'll go back to this later with a slightly larger wing area and the same powerplant and batteries.

The 9-volt NiMh battery is pretty good capacity for it's weight. It works well in the Electric Mite.

I just can't seem to find the $$$ to get one of those really light sky hooks hybrid receivers so I have to build micro models that can lift a GWS RX, ESC and batteries to power them and a motor.

[Chris]

I've wondered how it'd fly with 6 of those 70 mah NiMH cells. While I'm sure the motor wouldn't complain too much, I fear it'd be pushing those little wings. One of the benefits of keeping everything as light as possible is that during a crash there's just not a whole lot of kinetic energy to brake things.

Yea, the receiver and especially the servos were a hard swallow. I had been eyeing them for many months before splurging. It's unfortunate these things are so expensive because, I'll tell 'ya, I'm having a ball with this Thistle, but it'll just end up collecting dust once I transfer the hardware to another plane - I sure can't afford a pair of these servos and a receiver for each bird...

[james_a_moles]

Is that the new KP-00 from SH&R, or is that your own gearing? How much does it weigh?


James

[ 06-27-2001: Message edited by: james_a_moles ]

[Chris]

I bought it from Dave Lewis, but yes, it is the new one with the ring gear. The weight is still 8 grams w/prop.