RE: Shark 21
Yes, it is based on the Stinger 21.
Both come from the Stinger 40.
I have scaled down the Stinger 40.
The Shark is also made for electric.
It has an opening for cooling on the front.
I have designed the Stinger 40 for a Nelson FIRE.
It flies very fast, use 3mm rods for the Aileron or 4-40.
It my first flight 2mm steel was broken on one aileron.
I was lucky the engine was running rich.
Regards,
Look.