Discus/DG-300 performance difference

[ddg.p...@gmail.com]

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

[SoaringXCellence]

Performance is only part of the picture: 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

[marc....@gmail.com]

On Friday, May 8, 2015 at 6:20:38 PM UTC-7, ddg.p...@gmail.com 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

[Bob Whelan]

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.

[Jonathan St. Cloud]

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.

[marc....@gmail.com]

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.

[WaltWX]

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

[uncl...@ix.netcom.com]

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

[Jonathan St. Cloud]

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.

[John]

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

[ddg.p...@gmail.com]

Hi, I'm interested by your suggestion of the ASW 24,which I hadn't really considered. I have heard that they are trickier to thermal well, which may be a disadvantage when scratching being a relatively novice cross country pilot. Did you find any trouble in that regard?

[Jonathan St. Cloud]

On Saturday, May 9, 2015 at 10:56:24 AM UTC-7, ddg.p...@gmail.com wrote:
> Hi, I'm interested by your suggestion of the ASW 24,which I hadn't really considered. I have heard that they are trickier to thermal well, which may be a disadvantage when scratching being a relatively novice cross country pilot. Did you find any trouble in that regard?

My first glider was a used ASW-24. It had 6 hours on it! I was a new glider pilot and wanted a safe easy to fly machine for spreading my wings to fly far and fast. I was very comfortable in this ship. The only problem I had was the experienced pilots telling me that I needed to thermal slower, turns out I was right, the 24 does need to be thermaled a bit faster. After the first year I got the new winglets and that made it even a better glider! The human ergonomics, are well thought through, you can touch the instrument panel, the visibility is great, control harmony is the nicest of anything I have flown, safety cockpit, with Murray dump value the entire water ballast evacuates in two minutes. I did also find with water, it was best not to load it past 10.5 lb, even though you can load it higher.

I am bigger than most other pilots, 210 pounds very fit, but with broad shoulders 6 feet tall. I fit very well and in fact I fit very well in all the AS gliders, the same cannot be said for the LS or S-H with the "a" fuselage.

I have had a number of gliders and the ASW-24 is still one of my two favorite gliders. The other favorite glider was my Nimbus 4, but I did a lot of work on her to make it such a great glider, (still wish I had kept her) but I had gotten out of the sport for many years. "I am back", now.

[Charlie M. (UH & 002 owner/pilot)]

On Saturday, May 9, 2015 at 1:56:24 PM UTC-4, ddg.p...@gmail.com wrote:
> Hi, I'm interested by your suggestion of the ASW 24,which I hadn't really considered. I have heard that they are trickier to thermal well, which may be a disadvantage when scratching being a relatively novice cross country pilot. Did you find any trouble in that regard?

The 24 is not hard to thermal, but I will admit, it's a better thermalling glider with decent winglets on it. I have flown a stock 24, "slip-on winglets" as well as a few "cut the tips off & do it better" winglets.
Any of the tips help, later models allowed you to fly thermals a lot easier.
In my view, the "Murray/Nixon" tips were the best to use.

[Jonathan St. Cloud]

I had never heard of slip on winglets for the ASW-24. I bought factory winglets and I imagine virtually all ASW-24's have winglets so that should be a non-issue. As stated before the ASW-24 is a great glider and is worthy of consideration for a new or experienced pilot. Standard class is nice for new pilots, less to think about just fly. The standards lose out on the high end of the polar as compared to flapped ships but that really will not be a factor most pilots.

[uncl...@ix.netcom.com]

On Sunday, May 10, 2015 at 12:30:33 AM UTC-4, Jonathan St. Cloud wrote:
> I had never heard of slip on winglets for the ASW-24. I bought factory winglets and I imagine virtually all ASW-24's have winglets so that should be a non-issue. As stated before the ASW-24 is a great glider and is worthy of consideration for a new or experienced pilot. Standard class is nice for new pilots, less to think about just fly. The standards lose out on the high end of the polar as compared to flapped ships but that really will not be a factor most pilots.

"Slip on" winglets were an interim way to do winglet development on the '24 before Gerhard had started working on the winglet for the '24. Later we cut the tips off to match factory configuration and continued the development based on that. It worked out well with almost 40 sets installed.
FWIW
UH

[reda...@elay.media.pl]

How costly is it to put a nose hook on DG300?

Does anyone know?

S

[Mike Yankee]

I've owned a DG-300 since the early nineties and have 2000+ hours in type. This includes a lot of Allegheny ridge flying and several 1000-km flights. Here are my comments, some of which echo others. Overall I'm glad to have chosen this ship and would replace it, if I had to, with another one.

+ Very "honest" airplane; no mean tricks
+ DG canopy/visibility, warm feet in cold wx yet not intolerable in summer
+ Comfortable seating position
+ 5-inch mainwheel with good brake energy
+ Pneumatic tailwheel
+ Performance very close to original Discus, maybe a tad worse at 75-80 KIAS and a tad better at higher speeds
+ Only minor L/D loss with rain, insect accretion
+ Good longitudinal stability; excellent ridge ship (esp. ith water)
+ Easy rigging (though wings are heavy)
+ May be priced lower than equivalent Discus
+ Experimental certification

- DG parts/support extortion
- DG parts/support extortion (worth at least a second mention...)
- DG parts/support extortion (... and a third)
- Underwing blowholes can clog (turbulator tape probably better)
- DG-300 ailerons are a bit heavy and it somewhat blacks the sexy, natural feel of other ships (Discus, LS-4, etc.) when thermaling. This said, its roll rate and climb are comparable.
- Cockpit ventilation may be inadequate for hot climates but mods are available
- While DG gelcoat is generally excellent, some ships have cracking, alligatoring, yellowing, etc. due to inconsistent QC at the Elan factory.

[PBA]

Don't put a nose hook on the DG!!
No reason to, I was also afraid of the CG hook and then flew it and it's a non-issue on my DG 100. Great rudder control and no wing drop makes T.O easy.
Besides, when your club finally buys that winch, you'll be ready to GO :)

[reda...@elay.media.pl]

Do winglets make any real difference in terms of handling?

CoG max front. Does it adversely influence handling?

S

[uncl...@ix.netcom.com]

First question- It depends upon the glider. Some gliders have significantly improved handling at low speeds when winglets are installed.
Second question- forward CG adds stability and accordingly can reduce response to maneuvering inputs.
UH