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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
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 Posted: Sun Oct 19, 2008 10:23 pm Post subject: Dive test |
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Friday we managed to get all the ducks (i.e., FAA and paperwork) lined up and we flew the dive tests.
Well, as it turns out, a Piper Malibu CAN be used to pace a Tiger, but it isn't easy. I had to stand the TIger on it's nose to get it to 220 mph. A Malibu at the same angle of decent screams right by the Tiger, even with the power at cutoff. We tried it twice.
Then, we tried a much shallower dive and ran out of altitude before I got it to 190 mph (redline is 200 mph, target speed was 230 mph).
SOOOOOO, as it turns out, the gear on a Malibu can be extended at 170 knots and can be flown to 201 knots with the gear down. We needed 195 knots (224 mph, due to the position error on the Malibu.) to make the dive count. So far so good.
The 4th test proved that the Malibu, with the gear hanging down, has about the same drag as a Tiger. We were close.
On the fifth test, with the Malibu alongside the Tiger, we went to 200 knots. Next step, we wait to see if the FAA will accept the video and flight data.
--------------------------------------------
Now, for the rest of the story.
On the first dive test, we saw 240 mph on the Tiger. It wasn't easy.
On the second dive test, the air got a little rough=2 0just above the beginning of the yellow arc so we knocked off the test. The Malibu still blew by like I was parked.
On the third test, we got to 190 mph before I knocked of the test due to my own minimum altitude limit (5000 AGL)
On the 4th test (Malibu with its gear down and 100 feet off my left wing), we easily got to 220 MPH indicated. Unfortunately, the indicated in the Malibu showed we were too slow by about 6 mph.
On the 5th test, again with the Malibu about 100 feet off my left wing, gear down, we got to 235 mph on the Tiger; 200 knots on the Malibu.
Word of note: You will never even get close the the redline on a Tiger. Pointing the plane nearly straight down, at 190 mph, it stops accelerating with the engine at 2650 rpm. I had to nudge the throttle to cut the drag from the prop in order to get past 220 mph. It's very difficult to get to the plane's redline with a fixed pitch prop. Clearly, with a constant speed prop, this test would have been a whole lot easier.
At 240 mph, the plane is as smooth as glass. It takes a tremendous amount of forward stick to get it to dive at those speeds. Recovery is nothing more than relaxing the pressure on the yoke. We never experienced more than a little over 1g pulling out of a dive. About a 5000 f oot loss in altitude. Very stable plane. The FAA inspector was impressed. Nuff said.
Oh, yea, the cowling didn't bulge out or do anything it wasn't supposed to do.
[quote][b]
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Gary
AuCountry Aviation
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flyv35b(at)minetfiber.com
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| Posted: Mon Oct 20, 2008 4:33 am Post subject: Dive test |
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Congratulations on the successful test and integrity of the cowling! Very interesting info, Gary.
I guess this test shows the much lower drag coefficient of the Malibu. But maybe more importantly the effect of a CS prop, in a power off dive at least. It would be interesting to know how much of the difference is caused by the fixed pitch prop and how much by just the airframe drag. Sounds like you made a good choice for a chase plane.
I think there has been discussion before about the Grumman airfoil resulting in a large increase in airfoil drag, starting somewhere over 170 mph, and pitching moment which results in a lot of tail trim drag. With the high redline speed, it would be interesting to see what a different airfoil and a CS prop would do for this plane in reducing drag.
Cliff
[quote] ---
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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
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| Posted: Mon Oct 27, 2008 10:43 am Post subject: Dive test |
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66% power, 122 indicated, 8500 feet, 126 GPS ground speed, 2650 rpm,
142 True Airspeed
Pushing a 15 knot headwind
9.3 gph
Sent from my iPhone
On Oct 20, 2008, at 12:22 AM, teamgrumman(at)aol.com (teamgrumman(at)aol.com) wrote:
[quote] Friday we managed to get all the ducks (i.e., FAA and paperwork) lined up and we flew the dive tests.
Well, as it turns out, a Piper Malibu CAN be used to pace a Tiger, but it isn't easy. I had to stand the TIger on it's nose to get it to 220 mph. A Malibu at the same angle of decent screams right by the Tiger, even with the power at cutoff. We tried it twice.
Then, we tried a much shallower dive and ran out of altitude before I got it to 190 mph (redline is 200 mph, target speed was 230 mph).
SOOOOOO, as it turns out, the gear on a Malibu can be extended at 170 knots and can be flown to 201 knots with the gear down. We needed 195 knots (224 mph, due to the position error on the Malibu.) to make the dive count. So far so good.
The 4th test proved that the Malibu, with the gear hanging down, has about the same drag as a Tiger. We were close.
On the fifth test, with the Malibu alongside the Tiger, we went to 200 knots. Next step, we wait to see if the FAA will accept the video and flight data.
--------------------------------------------
Now, for the rest of the story.
On the first dive test, we saw 240 mph on the Tiger. It wasn't easy.
On the second dive test, the air got a little rough 0just above the beginning of the yellow arc so we knocked off the test. The Malibu still blew by like I was parked.
On the third test, we got to 190 mph before I knocked of the test due to my own minimum altitude limit (5000 AGL)
On the 4th test (Malibu with its gear down and 100 feet off my left wing), we easily got to 220 MPH indicated. Unfortunately, the indicated in the Malibu showed we were too slow by about 6 mph.
On the 5th test, again with the Malibu about 100 feet off my left wing, gear down, we got to 235 mph on the Tiger; 200 knots on the Malibu.
Word of note: You will never even get close the the redline on a Tiger. Pointing the plane nearly straight down, at 190 mph, it stops accelerating with the engine at 2650 rpm. I had to nudge the throttle to cut the drag from the prop in order to get past 220 mph. It's very difficult to get to the plane's redline with a fixed pitch prop. Clearly, with a constant speed prop, this test would have been a whole lot easier.
At 240 mph, the plane is as smooth as glass. It takes a tremendous amount of forward stick to get it to dive at those speeds. Recovery is nothing more than relaxing the pressure on the yoke. We never experienced more than a little over 1g pulling out of a dive. About a 5000 f oot loss in altitude. Very stable plane. The FAA inspector was impressed. Nuff said.
Oh, yea, the cowling didn't bulge out or do anything it wasn't supposed to do.
[b]
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Gary
AuCountry Aviation
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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
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| Posted: Mon Oct 27, 2008 11:27 am Post subject: Dive test |
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12000 ft. 7C OAT. 117 ind. 120 GPS. 2650 rpm. 62% pwr.
142 TAS.
Sent from my iPhone
On Oct 19, 2008, at 11:22 PM, teamgrumman(at)aol.com (teamgrumman(at)aol.com) wrote:
[quote] Friday we managed to get all the ducks (i.e., FAA and paperwork) lined up and we flew the dive tests.
Well, as it turns out, a Piper Malibu CAN be used to pace a Tiger, but it isn't easy. I had to stand the TIger on it's nose to get it to 220 mph. A Malibu at the same angle of decent screams right by the Tiger, even with the power at cutoff. We tried it twice.
Then, we tried a much shallower dive and ran out of altitude before I got it to 190 mph (redline is 200 mph, target speed was 230 mph).
SOOOOOO, as it turns out, the gear on a Malibu can be extended at 170 knots and can be flown to 201 knots with the gear down. We needed 195 knots (224 mph, due to the position error on the Malibu.) to make the dive count. So far so good.
The 4th test proved that the Malibu, with the gear hanging down, has about the same drag as a Tiger. We were close.
On the fifth test, with the Malibu alongside the Tiger, we went to 200 knots. Next step, we wait to see if the FAA will accept the video and flight data.
--------------------------------------------
Now, for the rest of the story.
On the first dive test, we saw 240 mph on the Tiger. It wasn't easy.
On the second dive test, the air got a little rough 0just above the beginning of the yellow arc so we knocked off the test. The Malibu still blew by like I was parked.
On the third test, we got to 190 mph before I knocked of the test due to my own minimum altitude limit (5000 AGL)
On the 4th test (Malibu with its gear down and 100 feet off my left wing), we easily got to 220 MPH indicated. Unfortunately, the indicated in the Malibu showed we were too slow by about 6 mph.
On the 5th test, again with the Malibu about 100 feet off my left wing, gear down, we got to 235 mph on the Tiger; 200 knots on the Malibu.
Word of note: You will never even get close the the redline on a Tiger. Pointing the plane nearly straight down, at 190 mph, it stops accelerating with the engine at 2650 rpm. I had to nudge the throttle to cut the drag from the prop in order to get past 220 mph. It's very difficult to get to the plane's redline with a fixed pitch prop. Clearly, with a constant speed prop, this test would have been a whole lot easier.
At 240 mph, the plane is as smooth as glass. It takes a tremendous amount of forward stick to get it to dive at those speeds. Recovery is nothing more than relaxing the pressure on the yoke. We never experienced more than a little over 1g pulling out of a dive. About a 5000 f oot loss in altitude. Very stable plane. The FAA inspector was impressed. Nuff said.
Oh, yea, the cowling didn't bulge out or do anything it wasn't supposed to do.
[b]
| | - The Matronics TeamGrumman-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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_________________
Gary
AuCountry Aviation
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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
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| Posted: Mon Oct 27, 2008 11:33 am Post subject: Dive test |
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Book speed for last one is 132 TAS
Sent from my iPhone
On Oct 19, 2008, at 11:22 PM, teamgrumman(at)aol.com (teamgrumman(at)aol.com) wrote:
[quote] Friday we managed to get all the ducks (i.e., FAA and paperwork) lined up and we flew the dive tests.
Well, as it turns out, a Piper Malibu CAN be used to pace a Tiger, but it isn't easy. I had to stand the TIger on it's nose to get it to 220 mph. A Malibu at the same angle of decent screams right by the Tiger, even with the power at cutoff. We tried it twice.
Then, we tried a much shallower dive and ran out of altitude before I got it to 190 mph (redline is 200 mph, target speed was 230 mph).
SOOOOOO, as it turns out, the gear on a Malibu can be extended at 170 knots and can be flown to 201 knots with the gear down. We needed 195 knots (224 mph, due to the position error on the Malibu.) to make the dive count. So far so good.
The 4th test proved that the Malibu, with the gear hanging down, has about the same drag as a Tiger. We were close.
On the fifth test, with the Malibu alongside the Tiger, we went to 200 knots. Next step, we wait to see if the FAA will accept the video and flight data.
--------------------------------------------
Now, for the rest of the story.
On the first dive test, we saw 240 mph on the Tiger. It wasn't easy.
On the second dive test, the air got a little rough 0just above the beginning of the yellow arc so we knocked off the test. The Malibu still blew by like I was parked.
On the third test, we got to 190 mph before I knocked of the test due to my own minimum altitude limit (5000 AGL)
On the 4th test (Malibu with its gear down and 100 feet off my left wing), we easily got to 220 MPH indicated. Unfortunately, the indicated in the Malibu showed we were too slow by about 6 mph.
On the 5th test, again with the Malibu about 100 feet off my left wing, gear down, we got to 235 mph on the Tiger; 200 knots on the Malibu.
Word of note: You will never even get close the the redline on a Tiger. Pointing the plane nearly straight down, at 190 mph, it stops accelerating with the engine at 2650 rpm. I had to nudge the throttle to cut the drag from the prop in order to get past 220 mph. It's very difficult to get to the plane's redline with a fixed pitch prop. Clearly, with a constant speed prop, this test would have been a whole lot easier.
At 240 mph, the plane is as smooth as glass. It takes a tremendous amount of forward stick to get it to dive at those speeds. Recovery is nothing more than relaxing the pressure on the yoke. We never experienced more than a little over 1g pulling out of a dive. About a 5000 f oot loss in altitude. Very stable plane. The FAA inspector was impressed. Nuff said.
Oh, yea, the cowling didn't bulge out or do anything it wasn't supposed to do.
[b]
| | - The Matronics TeamGrumman-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?TeamGrumman-List |
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_________________
Gary
AuCountry Aviation
Home of Team Grumman |
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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
|
| Posted: Mon Oct 27, 2008 11:33 am Post subject: Dive test |
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|
8.3 gph on the last one
Sent from my iPhone
On Oct 19, 2008, at 11:22 PM, teamgrumman(at)aol.com (teamgrumman(at)aol.com) wrote:
[quote] Friday we managed to get all the ducks (i.e., FAA and paperwork) lined up and we flew the dive tests.
Well, as it turns out, a Piper Malibu CAN be used to pace a Tiger, but it isn't easy. I had to stand the TIger on it's nose to get it to 220 mph. A Malibu at the same angle of decent screams right by the Tiger, even with the power at cutoff. We tried it twice.
Then, we tried a much shallower dive and ran out of altitude before I got it to 190 mph (redline is 200 mph, target speed was 230 mph).
SOOOOOO, as it turns out, the gear on a Malibu can be extended at 170 knots and can be flown to 201 knots with the gear down. We needed 195 knots (224 mph, due to the position error on the Malibu.) to make the dive count. So far so good.
The 4th test proved that the Malibu, with the gear hanging down, has about the same drag as a Tiger. We were close.
On the fifth test, with the Malibu alongside the Tiger, we went to 200 knots. Next step, we wait to see if the FAA will accept the video and flight data.
--------------------------------------------
Now, for the rest of the story.
On the first dive test, we saw 240 mph on the Tiger. It wasn't easy.
On the second dive test, the air got a little rough 0just above the beginning of the yellow arc so we knocked off the test. The Malibu still blew by like I was parked.
On the third test, we got to 190 mph before I knocked of the test due to my own minimum altitude limit (5000 AGL)
On the 4th test (Malibu with its gear down and 100 feet off my left wing), we easily got to 220 MPH indicated. Unfortunately, the indicated in the Malibu showed we were too slow by about 6 mph.
On the 5th test, again with the Malibu about 100 feet off my left wing, gear down, we got to 235 mph on the Tiger; 200 knots on the Malibu.
Word of note: You will never even get close the the redline on a Tiger. Pointing the plane nearly straight down, at 190 mph, it stops accelerating with the engine at 2650 rpm. I had to nudge the throttle to cut the drag from the prop in order to get past 220 mph. It's very difficult to get to the plane's redline with a fixed pitch prop. Clearly, with a constant speed prop, this test would have been a whole lot easier.
At 240 mph, the plane is as smooth as glass. It takes a tremendous amount of forward stick to get it to dive at those speeds. Recovery is nothing more than relaxing the pressure on the yoke. We never experienced more than a little over 1g pulling out of a dive. About a 5000 f oot loss in altitude. Very stable plane. The FAA inspector was impressed. Nuff said.
Oh, yea, the cowling didn't bulge out or do anything it wasn't supposed to do.
[b]
| | - The Matronics TeamGrumman-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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Gary
AuCountry Aviation
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robsherwin(at)AOL.COM
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| Posted: Mon Oct 27, 2008 11:37 am Post subject: Dive test |
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What was your cruise weight (approximately)? That's look pretty incredible, Gary.
Rob Sherwin 9853U
--
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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
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| Posted: Mon Oct 27, 2008 11:56 am Post subject: Dive test |
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11000 ft. 8.1 gph. 115 ind. 10 OAT. 60% pwr.
139 TAS.
Book 129 TAS (at) 9.1 gph
Sent from my iPhone
On Oct 19, 2008, at 11:22 PM, teamgrumman(at)aol.com (teamgrumman(at)aol.com) wrote:
[quote] Friday we managed to get all the ducks (i.e., FAA and paperwork) lined up and we flew the dive tests.
Well, as it turns out, a Piper Malibu CAN be used to pace a Tiger, but it isn't easy. I had to stand the TIger on it's nose to get it to 220 mph. A Malibu at the same angle of decent screams right by the Tiger, even with the power at cutoff. We tried it twice.
Then, we tried a much shallower dive and ran out of altitude before I got it to 190 mph (redline is 200 mph, target speed was 230 mph).
SOOOOOO, as it turns out, the gear on a Malibu can be extended at 170 knots and can be flown to 201 knots with the gear down. We needed 195 knots (224 mph, due to the position error on the Malibu.) to make the dive count. So far so good.
The 4th test proved that the Malibu, with the gear hanging down, has about the same drag as a Tiger. We were close.
On the fifth test, with the Malibu alongside the Tiger, we went to 200 knots. Next step, we wait to see if the FAA will accept the video and flight data.
--------------------------------------------
Now, for the rest of the story.
On the first dive test, we saw 240 mph on the Tiger. It wasn't easy.
On the second dive test, the air got a little rough 0just above the beginning of the yellow arc so we knocked off the test. The Malibu still blew by like I was parked.
On the third test, we got to 190 mph before I knocked of the test due to my own minimum altitude limit (5000 AGL)
On the 4th test (Malibu with its gear down and 100 feet off my left wing), we easily got to 220 MPH indicated. Unfortunately, the indicated in the Malibu showed we were too slow by about 6 mph.
On the 5th test, again with the Malibu about 100 feet off my left wing, gear down, we got to 235 mph on the Tiger; 200 knots on the Malibu.
Word of note: You will never even get close the the redline on a Tiger. Pointing the plane nearly straight down, at 190 mph, it stops accelerating with the engine at 2650 rpm. I had to nudge the throttle to cut the drag from the prop in order to get past 220 mph. It's very difficult to get to the plane's redline with a fixed pitch prop. Clearly, with a constant speed prop, this test would have been a whole lot easier.
At 240 mph, the plane is as smooth as glass. It takes a tremendous amount of forward stick to get it to dive at those speeds. Recovery is nothing more than relaxing the pressure on the yoke. We never experienced more than a little over 1g pulling out of a dive. About a 5000 f oot loss in altitude. Very stable plane. The FAA inspector was impressed. Nuff said.
Oh, yea, the cowling didn't bulge out or do anything it wasn't supposed to do.
[b]
| | - The Matronics TeamGrumman-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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Gary
AuCountry Aviation
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GrummanDude
Joined: 15 Jan 2006
Posts: 926
Location: Auburn, CA
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| Posted: Mon Oct 27, 2008 8:05 pm Post subject: Dive test |
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Nearly full tanks, I was by myself. Flying from Salt Lake City to Auburn.
--
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Gary
AuCountry Aviation
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