Kawa rough landing?

On Tuesday, September 17, 2019 at 8:49:45 PM UTC-7, Eric Greenwell wrote:
BG wrote on 9/17/2019 8:17 PM:
Any time someone lands their motor glider with engine extended has to ask questions about what happen. No one would ever deliberately choose to land with a extended engine and expect the best outcome. It is like flying with full spoilers with no ability to change things, you are in uncharted territory. The right thing would have been to start the relight at a higher altitude, then it it does not work, retract the engine and fly a more controllable aircraft into the best options available. The fact the engine was still out tells a story about pilot errors and understanding.


I beg to differ...The rate of sink from an extended mast depends very much on the
glider. For example, my ASH26E lands easily with the mast extended, and it's
definitely NOT like flying with full spoilers. I've tried it a couple times, and
it was such a non-event, I decided it was pointless to practice anymore.

Generally, a pilot will land with the mast extended because it will not retract,
or because he is too busy landing to retract it. Of course, it will not glide as
far with the mast extended, so I don't begin a restart until I am within a mast-up
gliding distance of a good landing place - just in case it doesn't retract after a
failed start.

Want to know more about flying a self-launching sailplane? Get the "A Guide to
Self-Launching Sailplane Operation", where all this and much more is covered.

https://sites.google.com/site/motorg...ad-the-guide-1

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

"...so I don't begin a restart until I am within a mast-up
gliding distance of a good landing place - just in case it doesn't retract after a
failed start. " Just to highlight the salient point

Jonathan St. Cloud wrote on 9/18/2019 5:20 AM:
On Tuesday, September 17, 2019 at 8:49:45 PM UTC-7, Eric Greenwell wrote:
BG wrote on 9/17/2019 8:17 PM:
Any time someone lands their motor glider with engine extended has to ask questions about what happen. No one would ever deliberately choose to land with a extended engine and expect the best outcome. It is like flying with full spoilers with no ability to change things, you are in uncharted territory. The right thing would have been to start the relight at a higher altitude, then it it does not work, retract the engine and fly a more controllable aircraft into the best options available. The fact the engine was still out tells a story about pilot errors and understanding.


I beg to differ...The rate of sink from an extended mast depends very much on the
glider. For example, my ASH26E lands easily with the mast extended, and it's
definitely NOT like flying with full spoilers. I've tried it a couple times, and
it was such a non-event, I decided it was pointless to practice anymore.

Generally, a pilot will land with the mast extended because it will not retract,
or because he is too busy landing to retract it. Of course, it will not glide as
far with the mast extended, so I don't begin a restart until I am within a mast-up
gliding distance of a good landing place - just in case it doesn't retract after a
failed start.

Want to know more about flying a self-launching sailplane? Get the "A Guide to
Self-Launching Sailplane Operation", where all this and much more is covered.

https://sites.google.com/site/motorg...ad-the-guide-1

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

"...so I don't begin a restart until I am within a mast-up
gliding distance of a good landing place - just in case it doesn't retract after a
failed start. " Just to highlight the salient point

Not really the point I tried to make, which is many motorgliders do not "plummet"
or become less controllable because the mast is up, so you don't have to fear a
landing in that configuration. If you are flying a normal pattern, you just use
less spoiler, or turn base a bit earlier. The situation where the reduced mast-up
glide distance is an issue is a high restart many miles from your chosen landing
place. It's just one more factor in your arrival height calculation, along with
wind, wing loading, and bugs.


--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

On Wednesday, September 18, 2019 at 9:07:32 AM UTC-4, Eric Greenwell wrote:
...is many motorgliders do not "plummet" or become less controllable
because the mast is up

And, many DO plummet, with reduced control authority.
It is highly dependent on what kind of glider!
Don't assume...

Dave Nadler wrote on 9/18/2019 7:43 AM:
On Wednesday, September 18, 2019 at 9:07:32 AM UTC-4, Eric Greenwell wrote:
...is many motorgliders do not "plummet" or become less controllable
because the mast is up

And, many DO plummet, with reduced control authority.
It is highly dependent on what kind of glider!
Don't assume...

That's why I recommend owners try at least one airport landing with the mast up,
and engine stopped, so they know what to expect if it happens to them. The 26E,
with the gear out and mast up, reminds me of landing a Blanik.

I've never had anyone flying the usual PIK, DG, ASH, and Ventus self-launchers
mention plummeting or reduced control authority to me, but I'm sure there must be
some like that. What gliders have this plummet/control authority problem, and how
bad is the plummet (same as half spoiler, full spoiler, etc), and reduction in
control?

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf
,

On Wednesday, September 18, 2019 at 3:16:37 PM UTC-7, Eric Greenwell wrote:
Dave Nadler wrote on 9/18/2019 7:43 AM:
On Wednesday, September 18, 2019 at 9:07:32 AM UTC-4, Eric Greenwell wrote:
...is many motorgliders do not "plummet" or become less controllable
because the mast is up

And, many DO plummet, with reduced control authority.
It is highly dependent on what kind of glider!
Don't assume...

That's why I recommend owners try at least one airport landing with the mast up,
and engine stopped, so they know what to expect if it happens to them. The 26E,
with the gear out and mast up, reminds me of landing a Blanik.

I've never had anyone flying the usual PIK, DG, ASH, and Ventus self-launchers
mention plummeting or reduced control authority to me, but I'm sure there must be
some like that. What gliders have this plummet/control authority problem, and how
bad is the plummet (same as half spoiler, full spoiler, etc), and reduction in
control?

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf
,

This is true. I fly a DG800 and with the mask out the sink rate is 4-5 knots, so my glide ratio is roughly 4-5 less. Air starts are typically on down wind to a know good field with in a 10:1 glide. If I am over uncharted territory, I will initiate the restart at a much higher altitude, even this adds extra risk if the engine won't start and I can not retract. The manual clearly states that landing with the mask out can easily lead to a hard landing, especially if any spoilers are deployed, they recommend no spoilers and extra airspeed needed to overcome the added sink rate on touch down. If you were about to land in one of the most difficult fields in your career, why would you choose to make it extra complicated with a engine mask out.. That is if you were not still being wishful it would miraculously start working. I feel this is a critical moment every MG pilot will find themselves one day. So over unlandable or very difficult terrain the plan of action to relight needs to happen at a much higher altitude that will allow retracting if things don't work. With the mask out most gliders performance degrades and requires extra airspeed to reliably reduce the extra sink rate on touch down. We all make mistakes and learn from them. A glider with a mask out in a very difficult outlanding is not good planning, especially if the mask system is working and the engine is not. Those that don't fly a MG think we have some advantage, when indeed we need to terminate our flight as a glider at a higher altitude. If you want to roll the dice and try to restart from a low altitude, if it works great which most of the time it would, but when it does not you are disadvantaged and add plenty of risk. Of my friends who fly a similar glider, one did the right thing in a difficult landing in a known good short field deep in the woods, rather than try a restart he landed. The other landing short with his mask out hanging in the trees on another day.

BG

On Wed, 18 Sep 2019 15:16:31 -0700, Eric Greenwell
wrote:


I've never had anyone flying the usual PIK, DG, ASH, and Ventus self-launchers
mention plummeting or reduced control authority to me, but I'm sure there must be
some like that. What gliders have this plummet/control authority problem, and how
bad is the plummet (same as half spoiler, full spoiler, etc), and reduction in
control?

Arcus M - you ought to be able to find a operating handbook online.
WIth extended power plant the L/D decreases to 13/1 and minimum sink
rate to 443 fpm.

So far I've seen two DG-400s crash that were trying to land with
extended power plant and didn't reach the runway.

Cheers
Andreas

Andreas Maurer wrote on 9/19/2019 12:11 PM:
On Wed, 18 Sep 2019 15:16:31 -0700, Eric Greenwell
wrote:


I've never had anyone flying the usual PIK, DG, ASH, and Ventus self-launchers
mention plummeting or reduced control authority to me, but I'm sure there must be
some like that. What gliders have this plummet/control authority problem, and how
bad is the plummet (same as half spoiler, full spoiler, etc), and reduction in
control?

Arcus M - you ought to be able to find a operating handbook online.
WIth extended power plant the L/D decreases to 13/1 and minimum sink
rate to 443 fpm.

So far I've seen two DG-400s crash that were trying to land with
extended power plant and didn't reach the runway.

That's one, perhaps, but 443 fpm doesn't seem like "plummeting" to me. I'm
surprised it's so poor mast up, as I've read the PIK20E is 15:1 with the mast up,
and that's only a 15 meter glider with the engine on the mast, unlike the buried
engine in the Arcus M. How does mast up compare to half or full spoiler, and is
that measured with the gear down?

Here's another data point: the last time I flew my ASH26E, I stopped the engine
while thermalling, but did not lower the mast. The glider continued to climb at a
reduced rate in the thermal. Note that the mast is always left half extended to
cool for several minutes after an engine run, and the thermal climb is not
noticeably improved when the mast is finally fully retracted. So, NO plummet mode
on the 26E, and really don't think it's that much different from an 18 M Ventus or DG.


--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

Eric, thanks for the response. While you have been flying relatively high performance machines, I have chosen to go a different route. The challenge for me is doing more with less. I fly a very low performance bird and have been pursuing the goal of setting records and making long distance flights in a 22/1 L/D machine.

To successfully do this type of flying requires a completely different set of soaring skills than the ones you use. Namely, I have to become "comfortable" with multiple low saves on virtually every record flight due to the fact that I do not have the lift-finding-reach that comes with higher performance. As a direct corrolary, I have to also become very proficient in the evaluation and utilization of every available scrap of landable terrain. I don't have the luxury of many others who have the "wing power" to cross large tracts of ground considered unlamdable. For me to reach my goals, I have to intimately know the skills I mentioned previously.

While my situation would be considered extreme by many, it is not. It is simply returning to the type of flying that the soaring pioneers of the 50's and 60's did. But now it can be done with the benefits of modern "high performance" electronic aids such as flight computers, gps, active real time wx, and active tracking, all of which increase the safety and efficiency factors to points our pioneers could only have dreamt of.

All that being said, the skills and the repetitous practice needed to gain those skills (things the successfull pioneers all had) are things that, in my oinion, need to be brought back into vogue. In todays day and age, there is entirely too much dependance upon performance and motorized aid to save a fellow. Proof of this is clearly seen in the rash of fatalities we are seeing.

It is well, necessary, and good to have personal risk standards. I also have them. But what does one do when they find themselves in a pinch, when they find that they have inadvertantly put their tail in a crack. This is what is happening. Sure there are probably a few guys who are simply flying hell bent for leather and as a consequence getting themselves killed. But I think the vast majority of the fatalities and serious injury accidents we are seen are more of the former case, where guys are simply slightly over extended, and finding themselves in a predicament, have no idea how to handle it.

The main reason motorgliders like the Arcus see such a large decrease in performance with the mast up is that the engine bay doors remain open, and they are about six feet long. That's a huge amount of drag. When we installed jet engines in the Tst-14 and four Arcuses, we had the main doors close over the engine bay and two small "sub-doors" open around the engine mount. With the engine extended, we measured the L/D of the Arcus J (jet) at 38:1. The Arcus M gets 13:1 with engine extended.

On Thursday, September 19, 2019 at 3:11:04 PM UTC-4, Andreas Maurer wrote:
On Wed, 18 Sep 2019 15:16:31 -0700, Eric Greenwell
wrote:


I've never had anyone flying the usual PIK, DG, ASH, and Ventus self-launchers
mention plummeting or reduced control authority to me, but I'm sure there must be
some like that. What gliders have this plummet/control authority problem, and how
bad is the plummet (same as half spoiler, full spoiler, etc), and reduction in
control?

Arcus M - you ought to be able to find a operating handbook online.
WIth extended power plant the L/D decreases to 13/1 and minimum sink
rate to 443 fpm.

So far I've seen two DG-400s crash that were trying to land with
extended power plant and didn't reach the runway.

Cheers
Andreas

Some things to consider:

(1) The 'best' sink rate and LD with motor extended are at what speed?
Blue-line is what's quoted for many types, but that's typically much less
than minimum pattern speed, in turn much less than required for safe
round-out from high sink rate.

(2) Drag isn't just prop! In addition to gear doors, there's a
rather large radiator, plus the mast structure and lots of other
bits hanging out in the breeze.

(3) Some models have been fitted with different props over time.
So, your mileage (and plumetting) may vary.

The Ventus 2CM I owned was a real plummeter.
It had significantly reduced pitch and rudder authority
and reduced yaw stability with engine out.
In factory briefing I was warned to be extremely careful not to stall it .
ArcusM engine-out was much less exciting, by far.

I landed both motor out after assorted failures.
The ArcusM was no problem, but the V2CM was pretty exciting.

Hope that helps,
Best Regards, Dave