Kawa rough landing?

On Thursday, September 26, 2019 at 3:21:49 PM UTC-4, 5Z wrote:
IMHO, the dire warnings about poor LD on the POH are there to avoid any
liability if someone decides to sue after an engine extended mishap.

Eric and 5Z - Please don't ASSUME that all gliders are as benign as 26
with motor out and stopped. They are not. You are doing the community a
great disservice by ASSUMING that its not a big problem for some gliders.
Including types with many in service.

Please be safe out there,
Best Regards, Dave

On Thursday, September 26, 2019 at 1:13:07 PM UTC-7, Eric Greenwell wrote:
5Z wrote on 9/26/2019 12:21 PM:
lowered it to the slightly extended cooling position.

The "slightly extended cooling position" is about 30 degrees from the fuselage.
There is still all the stuff hanging in the breeze: the propeller, the radiator,
almost the entire mast, and the doors are fully open. It looks dreadfully draggy
to a pilot circling in the same thermal with you, but it's just like Tom says: the
drag is so small, you don't know it's there.

--
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

Right - here is a flight where I forgot to complete the cool-down process and flew for 3 hours with the prop in that position:
https://www.onlinecontest.org/olc-3....l?dsId=7393456
It is really hard to determine the glide degradation with the prop out, but I am sure there is some.

Tom

On Thursday, September 26, 2019 at 5:57:40 PM UTC-7, Dave Nadler wrote:
On Thursday, September 26, 2019 at 3:21:49 PM UTC-4, 5Z wrote:
IMHO, the dire warnings about poor LD on the POH are there to avoid any
liability if someone decides to sue after an engine extended mishap.

Eric and 5Z - Please don't ASSUME that all gliders are as benign as 26
with motor out and stopped. They are not. You are doing the community a
great disservice by ASSUMING that its not a big problem for some gliders.
Including types with many in service.

Please be safe out there,
Best Regards, Dave

And you are doing the community a disservice by not naming those MGs. We are, at least, speaking from first-hand knowledge and ALWAYS state the gliders that we have direct experience with.

Tom

On Thursday, September 26, 2019 at 6:19:04 PM UTC-7, 2G wrote:
On Thursday, September 26, 2019 at 5:57:40 PM UTC-7, Dave Nadler wrote:
On Thursday, September 26, 2019 at 3:21:49 PM UTC-4, 5Z wrote:
IMHO, the dire warnings about poor LD on the POH are there to avoid any
liability if someone decides to sue after an engine extended mishap.

Eric and 5Z - Please don't ASSUME that all gliders are as benign as 26
with motor out and stopped. They are not. You are doing the community a
great disservice by ASSUMING that its not a big problem for some gliders.
Including types with many in service.

Please be safe out there,
Best Regards, Dave

And you are doing the community a disservice by not naming those MGs. We are, at least, speaking from first-hand knowledge and ALWAYS state the gliders that we have direct experience with.

Tom

Wow, something we both agree on Tom :-)

This started out discussing whether the extended engine on the GP14 would cause it to "plummet" if I recall some previous comments. We're providing some data points for what appears to be a similar looking pylon propeller to the GP14. The GP14 actually looks less draggy.
Now, the first generation MGs with the large and heavy engine on the pylon might be a completely different case. But we're not talking about them.

Tom 5Z

On Thursday, September 26, 2019 at 9:19:04 PM UTC-4, 2G wrote:
On Thursday, September 26, 2019 at 5:57:40 PM UTC-7, Dave Nadler wrote:
On Thursday, September 26, 2019 at 3:21:49 PM UTC-4, 5Z wrote:
IMHO, the dire warnings about poor LD on the POH are there to avoid any
liability if someone decides to sue after an engine extended mishap.

Eric and 5Z - Please don't ASSUME that all gliders are as benign as 26
with motor out and stopped. They are not. You are doing the community a
great disservice by ASSUMING that its not a big problem for some gliders.
Including types with many in service.

Please be safe out there,
Best Regards, Dave

And you are doing the community a disservice by not naming those MGs.
We are, at least, speaking from first-hand knowledge and ALWAYS state
the gliders that we have direct experience with.

As I posted above, the worst offender I've personally flown was my V2CM.
Even within a type, there have been different versions, especially changes
in prop. When stopped, the tapered prop of the 26 has less drag than some
of the earlier squarer props (didn't the original 26 have one of those??).

I don't have time to list all the gliders I've flown, but more than a few ;-)

On Friday, September 27, 2019 at 12:25:22 AM UTC-4, 5Z wrote:
This started out discussing whether the extended engine on the GP14 would
cause it to "plummet" if I recall some previous comments. We're providing
some data points for what appears to be a similar looking pylon propeller
to the GP14. The GP14 actually looks less draggy.

The data points you are providing are totally irrelevant to GP14.
The GP14 has no big radiator as required with gas power and a folding propeller,
though it does not close the engine-bay doors like Antares.
GP14 should be completely benign mast out and prop stopped. No plumetting.

On Friday, September 27, 2019 at 5:56:24 AM UTC-7, Dave Nadler wrote:
On Thursday, September 26, 2019 at 9:19:04 PM UTC-4, 2G wrote:
On Thursday, September 26, 2019 at 5:57:40 PM UTC-7, Dave Nadler wrote:
On Thursday, September 26, 2019 at 3:21:49 PM UTC-4, 5Z wrote:
IMHO, the dire warnings about poor LD on the POH are there to avoid any
liability if someone decides to sue after an engine extended mishap.

Eric and 5Z - Please don't ASSUME that all gliders are as benign as 26
with motor out and stopped. They are not. You are doing the community a
great disservice by ASSUMING that its not a big problem for some gliders.
Including types with many in service.

Please be safe out there,
Best Regards, Dave

And you are doing the community a disservice by not naming those MGs.
We are, at least, speaking from first-hand knowledge and ALWAYS state
the gliders that we have direct experience with.

As I posted above, the worst offender I've personally flown was my V2CM.
Even within a type, there have been different versions, especially changes
in prop. When stopped, the tapered prop of the 26 has less drag than some
of the earlier squarer props (didn't the original 26 have one of those??).

I don't have time to list all the gliders I've flown, but more than a few ;-)

That seems to be an issue with that particular MG, and not all MGs in general. It is like the varying spin behavior of different gliders. I will add another MG to the benign list: the DG505MB.

Tom

Dave Nadler wrote on 9/27/2019 5:56 AM:
On Thursday, September 26, 2019 at 9:19:04 PM UTC-4, 2G wrote:
On Thursday, September 26, 2019 at 5:57:40 PM UTC-7, Dave Nadler wrote:
On Thursday, September 26, 2019 at 3:21:49 PM UTC-4, 5Z wrote:
IMHO, the dire warnings about poor LD on the POH are there to avoid any
liability if someone decides to sue after an engine extended mishap.

Eric and 5Z - Please don't ASSUME that all gliders are as benign as 26
with motor out and stopped. They are not. You are doing the community a
great disservice by ASSUMING that its not a big problem for some gliders.
Including types with many in service.

Please be safe out there,
Best Regards, Dave

And you are doing the community a disservice by not naming those MGs.
We are, at least, speaking from first-hand knowledge and ALWAYS state
the gliders that we have direct experience with.

As I posted above, the worst offender I've personally flown was my V2CM.
Even within a type, there have been different versions, especially changes
in prop. When stopped, the tapered prop of the 26 has less drag than some
of the earlier squarer props (didn't the original 26 have one of those??).

I don't have time to list all the gliders I've flown, but more than a few ;-)

My 26E has the blunt "tongue depressor" style prop. It doesn't seem to make a
noticeable difference in drag, compared to the newer pointy prop.

We don't want a list of all the gliders you've flown, but just the ones with the
"plummet mode". Pilots often ask me about the characteristics of various
motorgliders, so I'd like to know which ones to caution the about. The V2CM is on
the list, but it's the only one I'm aware of.

--
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 Friday, September 27, 2019 at 6:06:21 AM UTC-7, Dave Nadler wrote:
The data points you are providing are totally irrelevant to GP14.
The GP14 has no big radiator as required with gas power and a folding propeller, though it does not close the engine-bay doors like Antares.
GP14 should be completely benign mast out and prop stopped. No plumetting.

Dave you have it backwards. My data points are for what looks like an obviously more draggy engine setup. And that setup is benign. So that leads me to assume the GP14 is benign as well. But until I fly one and play with it, I really don't know.

5Z