Thundergull
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A couple of questions regarding Earthstar in California. Airplane is Thunder Gull 2000:
1. Is Earthstar still a going concern? So far, no response to e-mail or phone, but my mate has only been trying for a couple of weeks. The web-site feels pretty current.
2. Peter is 1.87m and 95kg and 71. Roughly 6'2" and 200lbs. Any ideas on cockpit size, pilot weight and electric start?
3. Are the Gull 2000's only kits, or can one get a fully built one?
4. Does anyone know if there are any flying in Australia (or, at a pinch, NZ - though international flight restrictions could be a problem for a while yet).
Cheers,
Michael.
1. Is Earthstar still a going concern? So far, no response to e-mail or phone, but my mate has only been trying for a couple of weeks. The web-site feels pretty current.
2. Peter is 1.87m and 95kg and 71. Roughly 6'2" and 200lbs. Any ideas on cockpit size, pilot weight and electric start?
3. Are the Gull 2000's only kits, or can one get a fully built one?
4. Does anyone know if there are any flying in Australia (or, at a pinch, NZ - though international flight restrictions could be a problem for a while yet).
Cheers,
Michael.
I spoke to Mark Bierle (sp?) a couple of years ago. Nice guy. No idea about the Eartthstar business, but if it is in fact dead then someone needs to continue with that wing design on something other than the Titan
Rienk
Well-Known Member
I've visited Mark a couple times in the last few months.
EarthStar is going strong, though doing electric conversions of existing planes (I don't think they've sold a new plane in years). I believe he just picked up 5-7 Thundergull fuselages back east when he dropped off two electric conversions.
Their Zero electric system conversion is pretty slick - I just bought one for our little plane.
EarthStar is going strong, though doing electric conversions of existing planes (I don't think they've sold a new plane in years). I believe he just picked up 5-7 Thundergull fuselages back east when he dropped off two electric conversions.
Their Zero electric system conversion is pretty slick - I just bought one for our little plane.
I'd be interested to know what he's charging for those if you don't mind saying. I was dead set on getting an electric Thundergull at one point, but I just never pursued it. Rusty
Tornado Flyer
Well-Known Member
I got a reply to a question last month, but I do not think they are producing many planes.
Clanon
What's so good about the wing - the airfoil section?
I didn't think laminar flow was achievable on ultralight wings - at 2.3M (63mph, 4.75 ft chord) I would think the Reynolds number is too low to avoid turbulent flow. The wing surface would need to be pretty much optically flat and the profile exact. It would appear to be worse at stall, too, with a Re only just over 1M
That said, something doesn't add up if the published stall speed is correct. It would imply a real CLmax of 2+, which seems very high for such a low aspect wing.
What am I missing?
What's so good about the wing - the airfoil section?
I didn't think laminar flow was achievable on ultralight wings - at 2.3M (63mph, 4.75 ft chord) I would think the Reynolds number is too low to avoid turbulent flow. The wing surface would need to be pretty much optically flat and the profile exact. It would appear to be worse at stall, too, with a Re only just over 1M
That said, something doesn't add up if the published stall speed is correct. It would imply a real CLmax of 2+, which seems very high for such a low aspect wing.
What am I missing?
It didn't look like a laminar wing to me when I saw a Gull or Titan parked out at the local UL strip here a year or so ago. It looked like a well designed, clean, well-executed sheet metal wing, which automtically looks a lot more slick than what you are used to seeing on an ultalight. The wing looked more like something Dick VanGrunsven would have done for a UL experiment.
Wasn’t the RV-5 Dick’s foray into ultralights?
I like the thunder gull. I agree their website looks ancient.The airplane seems like it could be a good contender to the established UL types out there, if the price point is similar enough.
I like the thunder gull. I agree their website looks ancient.The airplane seems like it could be a good contender to the established UL types out there, if the price point is similar enough.
You have it backwards. It easier to get laminar flow at lower Reynolds numbers.
Doug
No, I believe the RV-5 was the motorglider project.
According to the designer of the Thundergull the performance comes from the detail design of the aerodynamics. Apparently the electric one is very quiet due to less turbulence at intersections and no unnecessary items sticking into the wind. This was in Sport Aviation about a year ago.
My understanding is that the motorglider project (based on the HP-18) has been inactive for many years, and is likely to remain inactive.
BJC
I
RV-11. The fifth issue of the 2008 RVator talked about it. The RVator Newsletter - Van's Aircraft Total Performance RV Kit Planes
I had a surprise lunch with Mark at Osh 2019, very nice guy. Turns out we had a lot in common and it turned into a meal at a nearby stand, it was one of the best experiences I had there 
I saw the electric conversion he's doing and had a seat in it, very roomy and comfy. I'd always been interested in his designs and he's still going strong despite being in a pretty bad accident a few years ago.
I saw the electric conversion he's doing and had a seat in it, very roomy and comfy. I'd always been interested in his designs and he's still going strong despite being in a pretty bad accident a few years ago.
Thanks.
That was 12 years ago. IIRC the details of my conversations with Van over the ensuing years, the project was inactive as of July 2019.
I would love to see it completed.
BJC
