Discus/DG-300 performance difference

Hi All
I'm currently in the market for my first glider and am looking at standard class machines of the Discus/DG-300 era. Having read the Johnson tests and many posts on this forum, I'm a bit confused as to where the touted performance difference comes from though. Dick Johnson found the polars to be near enough to identical and demonstrated so with a figure overlaying them in the DG-300 article. Despite that though, there seems to be a feeling in this forum that the Discus is a superior machine and competition results seem to support that. Given the extremely similar glide performance, is there some other factor which makes the Discus a better performer or are it's superior competition results simply because better/more competitive pilots bought it?



David

Performance is only part of the pictu handling and the effects of turbulence and bug/rain are rarely measured. A glider that is responsive and less demanding to fly may in fact perform better in competition just due to the lower demands on the pilot, allowing more energy to be used for the all important analysis and decision processes.

Just my $.02

On Friday, May 8, 2015 at 6:20:38 PM UTC-7, wrote:
Hi All
I'm currently in the market for my first glider and am looking at standard class machines of the Discus/DG-300 era. Having read the Johnson tests and many posts on this forum, I'm a bit confused as to where the touted performance difference comes from though. Dick Johnson found the polars to be near enough to identical and demonstrated so with a figure overlaying them in the DG-300 article. Despite that though, there seems to be a feeling in this forum that the Discus is a superior machine and competition results seem to support that. Given the extremely similar glide performance, is there some other factor which makes the Discus a better performer or are it's superior competition results simply because better/more competitive pilots bought it?

You'll get a lot of opinions, so here's mine. I've had about 50 hours in a Discus, 40 in a DG-300, and 300 or so in a DG-303 (which is really a minor tweak, mostly the addition winglets). The Discus is easier to fly well, lighter controls (particularly pitch), basically flies itself in thermals, has wing tanks for easy filling, and has a higher wing loading at gross. The DG has a more robust structure, better gelcoat, tougher landing gear with more ground clearance, lands more slowly (meaning shorter off-field landings), climbs slightly better with comparable wing loading, and has a more comfortable cockpit. One key factor, DIscus is still well supported by SH for free, DG requires paying an annual tax to them if you want such niceties as parts and technical bulletins. Never flew any contests in a Discus, but did in the 303. I never felt at a disadvantage against a Discus, in climb or head to head final glides.

Marc

On 5/8/2015 7:20 PM, wrote:
Hi All I'm currently in the market for my first glider and am looking at
standard class machines of the Discus/DG-300 era. Having read the Johnson
tests and many posts on this forum, I'm a bit confused as to where the
touted performance difference comes from though. Dick Johnson found the
polars to be near enough to identical and demonstrated so with a figure
overlaying them in the DG-300 article. Despite that though, there seems to
be a feeling in this forum that the Discus is a superior machine and
competition results seem to support that. Given the extremely similar glide
performance, is there some other factor which makes the Discus a better
performer or are it's superior competition results simply because
better/more competitive pilots bought it?



David


Have fun looking! It can be almost as much fun in its own way as soaring.

Never having flown either ship, but preceding you by a couple of decades on
the "general experience/observational" fronts, my working suspicion is you've
pretty much hit upon a key element in your post-ending question.

For where I imagine you to be on soaring's endless(ly fun!) soaring curve,
you'll find pilot differences *easily* overwhelm any polar differences between
"nominally similar" ships. In short, if you're getting whupped by a ship of
equal span, it's by the pilot, not your ship. (WARNING: The immediately
preceding statement can and will be debated loudly, urgently and endlessly by
soaring pilots everywhere, because it's fun to do so, nuances proliferate, and
opinions are as free as the advice given on RAS. But if you're honest with
yourself, the statement is fundamentally accurate!)

Bob W.

The DG-300 had issues during construction where the Elan team building the gliders, used non-certified construction methods with resulted in weakening of the wing structure. You should look into the history of the wing problems before purchasing a DG300.

On Friday, May 8, 2015 at 8:25:28 PM UTC-7, Jonathan St. Cloud wrote:
The DG-300 had issues during construction where the Elan team building the gliders, used non-certified construction methods with resulted in weakening of the wing structure. You should look into the history of the wing problems before purchasing a DG300.

A couple of Elan-built DG-300s (broken in unrelated accidents) were found to have a process problem related to the spar layup. Rather than find out if the problem was more pervasive or find an economical way to inspect, the DG factory apparently decided it was cheaper and easier to declare that all Elan and AMS built DG-300s and 303s (sold before the present management took over) had a problem, prohibited aerobatics, reduced the gross weight and Vne. No DG-300/303 has ever had a structural failure related to this issue. As a practical matter, unless one has DG-303 Acro (like I did) and wanted to do aerobatics, it doesn't much affect a 300 or 303 in day to day cross-country, or club class competition use.

By the way, a similar spar-related problem was also discovered with the Czech built Discus Cs and Duo Discus (one of which I was a part owner of at the time). SH went to some lengths to come up with a means of inspecting the affected gliders (involving cutting several holes and borescopes), and fixing those that were affected, at no expense to the owners. I still have a good deal of confidence in the structural integrity of the DG-300 and 303, not so current DG management.

I have close to 1000 hours in first a DG-300 followed by my Discus B flying cross country and competitively. My impressions mirror Marc's pretty close.. The DG-300 climbed well heavy but wouldn't run quite as well at higher speeds compared to the Discus B. Gel coat quality, pilot comfort and ruggedness all fall in favor of the DG-300. It has a smoother heavier car feel... probably because of the higher mass wings. The Discus B felt lighter and more responsive while maneuvering for thermals... also probably due to the lighter wing inertia mass.

A well flown DG-300 will do quite well against someone in a Discus B. But, as George Moffat said... even small performance differences add up for every minute of flight and the Discus will out perform a DG-300 in the long run.. But now, we have handicapped Club and Sport Classes, so either ship is competitive in those classes.

I like the SH factory and dealer support without the "DG Tax".

Very happy now with my Discus 2A.

Walt Rogers WX

On Friday, May 8, 2015 at 9:20:38 PM UTC-4, wrote:
Hi All
I'm currently in the market for my first glider and am looking at standard class machines of the Discus/DG-300 era. Having read the Johnson tests and many posts on this forum, I'm a bit confused as to where the touted performance difference comes from though. Dick Johnson found the polars to be near enough to identical and demonstrated so with a figure overlaying them in the DG-300 article. Despite that though, there seems to be a feeling in this forum that the Discus is a superior machine and competition results seem to support that. Given the extremely similar glide performance, is there some other factor which makes the Discus a better performer or are it's superior competition results simply because better/more competitive pilots bought it?



David

I would not discount the ASW-24. Performance is comparable. It requires slightly more technique to get best performance, but goes as well as the DiscusB. It also has a, for the time, break through technology safety cockpit and a real hydraulic wheel brake.
Among all of them the best choice will be decided by trailer, equipment, and condition.
Good luck
UH

I would second that on the ASW-24. I flew one for 600 hours. Maybe because it was my first glider, but I loved that bird. It was very responsive, and unlike S-H gliders, you can reach the instrument panel while strapped in. Plus the front hinged canopy, hydraulic disk brake, safety cockpit.... In my humble opinion the 24 goes as well as a discus and has many advantages over a discus. The downside of both the ASW-24 and LS-7 was that they needed to be thermaled a bit faster to get best climb rates..whatever you buy, the 300, 24 or Discus you will have a ship that you can fly many hours and miles.

I really love my DG-303 Acro with no Tax. Mine was built in 1998 under the new company so it is still covered. I am a very large guy and the DG-303 has big advantages with taller pilots. I love the big ailerons although the wiglets are kind of ugly but functional. The glider is overbuilt structurally which I like as I am a recreational flyer and not a racer. The Discus, ASW-24 and DG-303 are all great with different flavors and styles that match to different pilots. Many times it just comes down to what is for sale, where it's located, and most importantly what kind of trailer does it come with. When you buy used, the luxury of choice often get subverted by availability circumstances.
John