GRM airplanes... challenge style....

I've followed this guy for a while... he started in RC planes and has dabbled into some very strange ultralight planes using his knowledge of RC planes... 

here is his newest build.. 

https://youtu.be/aLpmJ97GXZQ

I've followed along with some of his builds too, they're pretty cool (and sometimes a bit sketchy). Ultra light licensing is a lot more lax in the land of the free then up here in the frozen E36M3-hole of Hoth for better or worse.

Adam

As a pilot, no berkeleying way am I setting foot near a $2000 aircraft. Spectacular failure at the Challenge? Shoots valves through the hood. Spectacular failure airborne? Lawn dart. Nope.

I have been flying a $2000 hang glider ;P

And for the record, it's not that ultralight licensing is lax... there is no ultralight licensing. That's the best part about ultralights. You pays your monies, and takes your chances.

Look up FAR part 103 if curious.

basic rules:

Don't fly in controlled airspace

Don't fly over populated areas

Don't fly when the sun is down

Yield right of way to all other aircraft

1 occupant allowed on vehicle

glider: 155 lb weight empty, 24 knot stall speed

powered: 254 lb weight empty, 24 knot stall speed, 55 knot max speed

powered: 5 gallons of fuel allowed

I think that's it. Did I miss any big ones?

Ultralights are a cool world. Included are paragliders, powered paramotors, hang gliders, rigid wing hang gliders, trikes etc etc... It's about as safe as you want to make it... Like most activities. You can take lessons, spend hours in sims, do thorough pre-flight inspections, and fly in big fields solely in really nice weather. 

Risk management is a big topic, and yes, there is a lot of energy involved with aircraft. It isn't necessarily suicide though.

https://youtu.be/RhbB0Bu6lAY

I used to Hang Glide, cool that it's a self regulating sport.  At the time the Hang Gliding Association (USHGA) divorced itself from anything with power.  The FAA was starting to step in with "if you leave the ground, you need a license".  It settled down to what it is today, but took a few years. 

As a pilot with a glider and light sport rating, I believe no one can be hurt by a little training.  I've been in thermals with the meter pegged at 1,000 fpm climb, can't imagine that in a dacron and aluminum rig.  And that posted home made thing is just scary!  Hopefully he won't hurt anyone but himself.

If you don't know anyone killed Hang Gliding, you will.

Don't get me wrong, I love ultralights. Ingenuity in staying under the 254lb limit is amazing. You need quality components to build a safe craft. You'll be hard pressed to do that under $2,000 without connections or a significant cashe "sitting on the shelf."

I watched that guy's previous DIY plane series. Pretty cool stuff. I don't think he's particularly imprudent as far as saftey, so I believe he'll probably be fine. 

I’m trying to think what it would feel like to drive my Challenge car off a cliff. 

SVreX said:

I’m trying to think what it would feel like to drive my Challenge car off a cliff. 

Depending on the height of the cliff that could be a safer bet than the OP's post.

Joke.  Lot's of respect for the dude.

He seems pretty skilled, I just hope he has scaled his engineering correctly.  Scaling up makes thing significantly weaker (proportional wise).  Getting some unexpected turbulence and snapping a wing spar that was only stressed for 2G is easily something you might not live through.

Although a competition to build the lowest cost / highest performance plane would be very interesting, you would not want to fly them.

Many people forget air doesn't scale. 

I need to remind myself that way back, when John Moody bolted an engine on the back of his Easy Riser, there where no specific ultralight parts-because ultralights didn't exist. 

I hope this guy stays safe, because it is cool.

I applaud the guys chutzpa. How he gets anything as big as his balls off the ground I don't know.

If this was a  Lotus 7 clone he was building, I would be all over the chance to go for a drive.

But it is not.

Not saying his welding is not good or his fits are terrible, but they are not what I want to be thinking about when the breakdown lane is 1000 feet below me. And I would be.

I used to work with a very talented race car builder  at a job where we fabricated and installed robotic test cells in factories. As a means of making a point about what was "Good enough" for me, he once asked me if I would fly in an airplane that I had built. And while the conversation was to make a point about the work we were doing at the time, I had to admit to myself that "No Berkeleying Way" was the answer." I have been trying to improve with that in mind ever since, but not there yet.

Pete

In reply to 914Driver :

USHPA controls a bunch of flying sites, but not all... So there are still rebels out there subject to the regulation of the laws of physics. IMO, hang gliding became much safer with the invention of luff lines, and washout tubes. The luffing dive is no longer a threat. The tuck and tumble could still happen through bad piloting or really bad weather. Overall tough, the sport is dangerous, but not as dangerous as it used to be. Some of the old timers I know have lost 20+ friends to the sport. You're probably right about having a friend die, but the same is true of GA, sad as it may be.

The electric Swift Light is it for me in the world of ultralights. It'd be very difficult to top that design. It can taxi, self launch, soar, self retrieve. 

In reply to NOHOME :

I didn't watch the full build. please tell me those welds are just tacked....

That’s the guy from TestFlite. At least that’s where I saw him. He’s brilliant.

On the topic of those welds, he did mention that they would be finished by someone else because he wasn’t an expert and wouldn’t risk his life to his welds...

In reply to gencollon :

Yeah, he does mention that he's going to have someone else finish weld it.  Thank goodness. 

Actually did not listen to the sound, so missed that bit about outsourcing the welding. But it was more the fitment of the tubes that I was worried about.

That said, if his welding contractor is good with it, then so am I.

Pete

I would fly in something i built. That's kind of the plan, eventually. 

ebonyandivory said:

That’s the guy from TestFlite. At least that’s where I saw him. He’s brilliant.

yup love some of his desighns... Flighttest has had some really neat people come through it's doors

this guy just amazes me and I guess he reminds me a lot of the DIY/can do attitude of a lot of what I see at the GRM challenge.