Best Overall Motorglider available today?

Nick Kennedy wrote on 9/15/2020 11:28 AM:
On Tuesday, September 15, 2020 at 12:19:11 PM UTC-6, Dan Daly wrote:
On Tuesday, September 15, 2020 at 1:48:13 PM UTC-4, Nick Kennedy wrote:
Didn't want to hijack the current FES tread so I thought I'd start a new one.
This topic came up over dinner a couple of weeks ago.

When you add all the following into a pot and stir, whats the "Best"
Say for Western Great Basin flying.

I think it may be the Carat, but I don't know much about it.
CX thinks its the DG 800 series, but all I know is since he bought that thing its been a endless battle to keep it running. But it does climb well.

FACTORS

Reliability
Maintenance required to keep it running
XC flyability, performance and control feel
Storability
Rigging
Initial cost
High density climb performance
Range
Cockpit layout and seating
Parts availability
Insurance cost
Landing gear complexity
Overall quality
Something thats available used this year maybe

"Something thats available used this year maybe
Not pie in the sky vaporware"

That helps narrow the field a bit, but what we really need to know mo

-What kind of flying do you intend - recreational, contests, badges, records,
safaris (assisted/unassisted)?

-what is your price limit?

-Are you able and willing to maintain it yourself?


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Wednesday, September 16, 2020 at 6:22:28 AM UTC-7, Eric Greenwell wrote:
Nick Kennedy wrote on 9/15/2020 11:28 AM:
On Tuesday, September 15, 2020 at 12:19:11 PM UTC-6, Dan Daly wrote:
On Tuesday, September 15, 2020 at 1:48:13 PM UTC-4, Nick Kennedy wrote:
Didn't want to hijack the current FES tread so I thought I'd start a new one.
This topic came up over dinner a couple of weeks ago.

When you add all the following into a pot and stir, whats the "Best"
Say for Western Great Basin flying.

I think it may be the Carat, but I don't know much about it.
CX thinks its the DG 800 series, but all I know is since he bought that thing its been a endless battle to keep it running. But it does climb well.

FACTORS

Reliability
Maintenance required to keep it running
XC flyability, performance and control feel
Storability
Rigging
Initial cost
High density climb performance
Range
Cockpit layout and seating
Parts availability
Insurance cost
Landing gear complexity
Overall quality
Something thats available used this year maybe

"Something thats available used this year maybe
Not pie in the sky vaporware"
That helps narrow the field a bit, but what we really need to know mo

-What kind of flying do you intend - recreational, contests, badges, records,
safaris (assisted/unassisted)?

-what is your price limit?

-Are you able and willing to maintain it yourself?


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1


I owned a DG400 for a few years, found it to be an excellent performing sailplane , the landing gear was perfectly fine, the engine faultless, and it was great fun to fly. I never needed any engine parts, but no doubt over time I would have. I now own a Sinus Flex. A lot of fun but way too low soaring performance unless you let the engine idle, but then that is not what soaring is about. I agree that the Stemme is too big, too complicated, too expensive, etc.

What we need is for a company to build a Sinus, or a Phoenix, or a Katana or any of those similar touring motorgliders with a 4 piece wing that has a 19 or 20 meter span. The outer tips need to come off easily (like my SInus Flex) but when removed the span would be 39 feet so it goes in any hangar. With more than a 15 meter span the soaring performance would likely be close to 40/1 L/D. The 4 stroke Rotax engines are really great, the cost could hardly increase very much, and it would be in the perfect sailplane sweet spot.

The Virus/Sinus are low performance and the view out when thermal
turning is appallingly bad.

The bubble canopy Taurus is better and in strong conditions seems to
go quite well, plus it has a Rotax engine not that heap of junk Solo
found in DG800x & others. You'd struggle to call it high performance.

The DG400 has the usual DG self collapsing U/C feature. Once you
know about this design triumph it's easy to keep the U/C in working
order. It's nice to fly and has really good performance in strong
conditions; the view out is excellent. The engine parts (at least in EASA
land) are not a problem and it's a Rotax not a Solo and it doesn't
regularly break its drive belt. The gel coat/finish is excellent, as usual

with DG. Dealing with DG as a company was a joy. The engine
management man/machine interface is very last century; if you have
three arms you will have no problem, it's nearly as bad as many current
turbo/self-launch gliders: plenty of scope for finger/brain malfunction.
The 400 wing section does NOT like rain or bugs. One of the four
Hoteliers (flaperons & air-brakes) is a tricky blind fiddle to fix &
secure.
Vibration related failures are a known issue: that said my "400" was
significantly more reliable than my much newer Solo powered DG808C
or my Antares 20E.

My choice would be a DG800A (basically a 400 type fuselage/Rotax
engine + DG800 type wings). It doesn't like rain or bugs either but is
significantly better than the DG400 as a glider.

I think all newer DG800x have a vastly improved "one-switch does it
all" engine management system that really is very good?

I've got lots of hours in someone else's Stemme S10, the Limbach
engined one, it was very reliable but the VP propellor overhaul costs
were eye watering even 20 years ago. It's a very competent glider but
big and heavy, not at its best scraping low on the rocks.

I can't think of anything polite to say about Wankel engines... a
vibration free engineers nightmare?

If economics are at all an issue just buy a proper sailplane and get a
tow: it's a FAR FAR cheaper way to fly.

Pipistrelle Apis is a fun sport glider with maybe 40:1 at best LD- 50 kts. Goes well up to 80 kts. Engine used to be Rotax 447 which is bombproof but don't know anything about the new engine install. Really stout carbon construction with 121 kts vne. Light wing load with no ballast so you can get bounced around pretty good on strong days at high speed.

Comfortable cockpit and easy handling. Spring trim could be better. 10,000 hour airframe and 300 hour engine. In 10 years I have 40 hours on the engine, 400 hours on the airframe. Seems to handle the obligatory vibrations well. Pretty much trouble free so far.

Good price point.

That is a curious statement. The Austro Wankel seems to be measurably more reliable than the Rotax as installed in the DG.

I will agree that tows are far more economical - provided you can get one. Of the four Great Basin soaring operations, 4 out of 4 experienced some period of reduced tow availability this year, a trend that is increasing.

On Wednesday, September 16, 2020 at 9:15:05 AM UTC-7, Dave Walsh wrote:
I can't think of anything polite to say about Wankel engines... a
vibration free engineers nightmare?

If economics are at all an issue just buy a proper sailplane and get a
tow: it's a FAR FAR cheaper way to fly.

Dave Walsh wrote on 9/16/2020 9:06 AM:
I can't think of anything polite to say about Wankel engines... a
vibration free engineers nightmare?

How is "vibration free" an "engineers nightmare"? It's certainly a pilots dream!
After 200 engine hours spread over 25 years, I have not had a significant
vibration induced problem! Try achieving that with a two stroke.

Here's some actual comparisons: a while ago, I searched the postings on the Wankel
powered Schleicher glider group for key words like "vibration", and also on the
DG/Solo group. There were few to found for the Wankel engine, and they were a
small minority of the issues discussed. The search of the DG/Solo group found a
LOT "vibration" issues, and they were the big majority problems.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

At 19:27 16 September 2020, Eric Greenwell wrote:
Dave Walsh wrote on 9/16/2020 9:06 AM:
I can't think of anything polite to say about Wankel engines... a
vibration free engineers nightmare?

How is "vibration free" an "engineers nightmare"? It's certainly a
pilots
dream!
After 200 engine hours spread over 25 years, I have not had a
significant
vibration induced problem! Try achieving that with a two stroke.

Here's some actual comparisons: a while ago, I searched the postings
on the
Wankel
powered Schleicher glider group for key words like "vibration", and
also on
the
DG/Solo group. There were few to found for the Wankel engine, and
they were
a
small minority of the issues discussed. The search of the DG/Solo
group
found a
LOT "vibration" issues, and they were the big majority problems.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email
me)

My poor use of English, perhaps I should have said the Wankel is an
engineering nightmare (without vibration problems)? Clearly some
pilots have reliable Wankel engines; others are not so fortunate. Luckily
we're in a democracy so we can choose which (unreliable) engine to
buy. Current DG models have Solo not Rotax engines. I don't like any of
them. There are some nice Japanese two strokes out there, just not in
any sailplane. Despite the reported lack of vibration the bolts holding
some Wankel engines together seem to have a habit of falling out?
Assuming all motor-gliders are unreliable seems a safe bet.

Dave Walsh wrote on 9/16/2020 1:11 PM:
Despite the reported lack of vibration the bolts holding
some Wankel engines together seem to have a habit of falling out?
Assuming all motor-gliders are unreliable seems a safe bet.

The 26E was not affected, so I am not an expert on it; however, my understanding
is it's a bolt problem, not vibration related. Seriously, it has so little
vibration, I can't imagine that it could break a bolt. Vibration is simply not an
issue in our Wankel powered gliders.

It is a bad bet to assume all motor-gliders are unreliable, when so many are quite
good. I have had fewer lost soaring days because I couldn't self-launch than when
I had to use tows, and I'm very glad to be a FORMER owner of towplane!

It is not a good bet to assume the engine will start when it is your only chance
of avoiding a crash. It's not just the engine that may malfunction, but the pilot
might make a mistake.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

The question comes down to what do you want, power-plane flying with some soaring ability or self-launch, self retrieve cross country sailplane? And how much money do you have?
For the latter mission, the ASH31 is right now a great glider. (Of course, my toy.) Strong climb performance -- I self-launch at Truckee, often 8000+ density altitude, with full water ballast, and no trouble. It has great cross country performance, keeping up well with 18m contest gliders. Its one limitation is not quite enough water ballast (legally), 10.8 lbs/sq foot. The 26 is a good substitute if you don't have lots of money. No 21 meter wings, top about 9.2 lbs, for much less money you lose a few MPH on your friend in a 31. The engine is very reliable.
I would not choose it though if I routinely wanted to fly 100s of miles under power and occasionally soar a bit.
John Cochrane BB

Very astute, Eric.

On 9/16/2020 3:20 PM, Eric Greenwell wrote:
It's not just the engine that may malfunction, but the pilot might
make a mistake.

--
Dan, 5J