banner
banner

10 Aug 2022, 01:25 [ UTC - 5; DST ]


Stevens Aerospace (Banner)



Reply to topic  [ 91 posts ]  Go to page Previous  1, 2, 3, 4, 5 ... 7  Next
Username Protected Message
 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 13:13 
Online


User avatar
 Profile




Joined: 11/08/12
Posts: 4482
Post Likes: +2465
Location: San Carlos, CA - KSQL
Aircraft: Mitsubishi MU-2B-40
Username Protected wrote:
… keep asking for actual info on flight manual veracity, which should be of general interest to everybody.

My MU2B-40 Solitaire (-10 engines) makes very close to book numbers in cruise.

_________________
-Jon C.


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 13:42 
Offline


User avatar
 Profile




Joined: 11/25/16
Posts: 1663
Post Likes: +1205
Location: CNC3
Aircraft: AEST
Username Protected wrote:
That would depend on how high you are, and how much energy was lost, turning onto each leg, but if IAS has not changed in 60 seconds, it is probably not going to change much more. A turbine airplane that is at a very high altitude, high angle of attack, and lower indicated airspeed, is going to take much longer to stabilize than a B-55 at low angle of attack.

In my case, an Aerostar and I'll probably do this at 10K, 15K and 20K.

So 10 mins per leg would be more than sufficient?


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 13:45 
Offline


User avatar
 Profile




Joined: 04/02/18
Posts: 232
Post Likes: +126
Location: M40, 20GA
Aircraft: RV-4
Username Protected wrote:
That would depend on how high you are, and how much energy was lost, turning onto each leg, but if IAS has not changed in 60 seconds, it is probably not going to change much more. A turbine airplane that is at a very high altitude, high angle of attack, and lower indicated airspeed, is going to take much longer to stabilize than a B-55 at low angle of attack.

In my case, an Aerostar and I'll probably do this at 10K, 15K and 20K.

So 10 mins per leg would be more than sufficient?


It shouldn’t take anywhere near that long, each leg only needs to be held long enough for airspeed to stabilize. Once it does, write down GS and track, then turn to the next heading.

Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 13:51 
Offline


 WWW  Profile




Joined: 01/12/10
Posts: 345
Post Likes: +678
Company: The Grand Galvez Hotel
Location: Dallas, Texas
Aircraft: Cessna TTx/CE S550
Username Protected wrote:
Folks, I recently test-flew an MU-2K in very good shape and got 253 ktas at 25,000' vs 289 ktas flight manual prediction for identical weight/alt/temp at max cruise power.

I know there are a thousand pitfalls in measuring performance and I promise to come back and report when, as I expect, this data point is confirmed/refuted. But for now, rather than present all the data for in-depth analysis, I'd really like to know from MU-2-experienced persons: do MU2s generally fly on book speeds, or a few knots slow, or all over the place..... or even if no one ever really checks them against the flight manual, so we don't really know.

For reference -- I hear that Beech flight manuals are pretty accurate, and I can verify that a Mooney 252 that I owned flew dead on book, within 1 knot and 0.1 gph.

Thanks in advance --



Charley Brown



Charley I had a K model withOUT the original engines (NOT the -10 engines) and it consistently did 280 Knots on 85GPH fuel flow. Something is very wrong or a gear door is sticking out lol...


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 14:37 
Offline


 Profile




Joined: 10/05/09
Posts: 211
Post Likes: +95
Location: Portland, Oregon
Aircraft: MU-2F
It would be good to know how heavy you were as well. My plane (F model with -1 engines) will be at ~250KTAS when leveling off at FL250 after taking off with full fuel, but will speed up to ~260KTAS as the tip tanks empty. Best speed I have seen so far is 272KTAS at FL240 at -32C. We were using just over 60gph at the time and EGTs were just below the bottom of the yellow arc.


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 15:39 
Offline



 Profile




Joined: 05/05/09
Posts: 4479
Post Likes: +4090
Aircraft: G44, R44, C501, C55
Username Protected wrote:
It would be good to know how heavy you were as well. My plane (F model with -1 engines) will be at ~250KTAS when leveling off at FL250 after taking off with full fuel, but will speed up to ~260KTAS as the tip tanks empty. Best speed I have seen so far is 272KTAS at FL240 at -32C. We were using just over 60gph at the time and EGTs were just below the bottom of the yellow arc.


My F wouldn't go to FL240 will full gas and 3 people but I did see 275kts TAS once out west int he winter at 220. Really an amazing airplane.


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 15:40 
Offline


 WWW  Profile




Joined: 08/24/13
Posts: 6381
Post Likes: +2649
Company: Aviation Tools / CCX
Location: KSMQ New Jersey
Aircraft: TBM700C2
Username Protected wrote:
On a normal IFR Pitot Static check do they run the Airspeed up to verify accuracy?


No, it is not part of the 2 year check. But you do need to connect to the pitot lines when running up the altitude, so most techs will look at it and _should_ let you know if it is off much.

Some OEM airframe inspections include an airspeed check.


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 18:12 
Offline


User avatar
 Profile




Joined: 03/17/08
Posts: 5354
Post Likes: +8939
Location: KMCW
Aircraft: B55 PII,F-1,L-2,OTW,
Username Protected wrote:
On a normal IFR Pitot Static check do they run the Airspeed up to verify accuracy?
I had them do it on my new Garmin panel just to make sure everything was reading right.

I guess I recall them doing it on our M-model, but we had the A/P disconnect plumbing in the pitot lines and they didn't match left to right.


A static check confirms the indicator and the tubing, but the installation error can be significant and it varies with AOA, hence the difference between IAS and CAS. A pitot tube under the wing is in a higher pressure area. To be accurate the rule of thumb is that the pitot tube needs to be 1/2 the wing chord distance in front of the leading edge to get ahead of the pressure wave in front of the wing.

_________________
Tailwinds,
Doug Rozendaal
MCW
Flight B-25 PBY 61.58,
Ground B25 GS, P-51 GS DPE renewal


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 19:58 
Offline


 Profile




Joined: 08/01/11
Posts: 5684
Post Likes: +2757
Location: In between the opioid and marijuana epidemics
Aircraft: 182, A36TC
We’re the flaps now r gear down?

_________________
Fly High,

Ryan Holt CFI

"Paranoia and PTSD are requirements not diseases"


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 20:41 
Offline


 Profile




Joined: 03/22/14
Posts: 78
Post Likes: +54
Location: KMYF/ Kamiah, ID
Aircraft: AC90, BE36, C210
Username Protected wrote:
On a normal IFR Pitot Static check do they run the Airspeed up to verify accuracy?


No, it is not part of the 2 year check. But you do need to connect to the pitot lines when running up the altitude, so most techs will look at it and _should_ let you know if it is off much.

Some OEM airframe inspections include an airspeed check.


My airspeed check was not done until I requested it. When I added the GI275 backup I found the g600 was off. The backup analog, co pilot, and GI275 all matched. The G600 was off. (3 percent slow). Twin turbine AC90.
There is no way to adjust the G600 airspeed, so the air-data computer would need to be replaced or debugged. If the MU2 has a G600, that’s just another variable to check.

Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 20:46 
Offline


 Profile




Joined: 10/07/18
Posts: 1837
Post Likes: +1161
Location: Columbus, Ohio
Aircraft: Baron 58, Lear 35
Username Protected wrote:
To be accurate the rule of thumb is that the pitot tube needs to be 1/2 the wing chord distance in front of the leading edge to get ahead of the pressure wave in front of the wing.

The MU2s I’ve worked on have the pitot tubes on the side of the fuselage, about even with, or slightly forward of, the lower edge of the windshield.


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 21:11 
Offline


User avatar
 Profile




Joined: 12/19/09
Posts: 235
Post Likes: +187
Company: Premier Bone and Joint
Location: Wyoming
Aircraft: BE90,HUSK,MU-2
Mine's a -10 K. Not sure on book numbers (since mine is modified and no longer ascribes to book) but those numbers you posted definitely sound off from what I've heard that others see. On a hot summer day when I'm heavy, it sometimes drops below 300kts. but most of the time it's about 305 summer and 315 or so winter. I've seen steady cruise speeds as low as 289 and as high as 330 kts TAS.
I think the MU-2 is a bit more weight and temperature dependent at altitude than (for example) my Aerostar was, likely due to 55#/sq ft loading. But no question most MU-2's seem to have plenty of "get up and go" as long as you don't take them too high.
Definitely do the 3 heading GPS test in flight next time and make sure the plane looks normal in the hangar (with controls neutralized, no spoilers or trim ailerons substantially off neutral [trim ailerons usually are off wing trailing edge just a bit after landing], and flaps fully retracted as they should be). You can see the nose gear and doors in the wing tank mirrors to insure they are fully retracted (same with landing lights that add a lot of drag when out). Make sure red gear light is out when retracted to ensure that MLG doors did fully close. Ensure plane is fully coordinated when doing the test runs. The Mits is very trim intensive in all axes and it will happily fly along rolled to one side or yawed to the side if the controls are set incorrectly or one engine has just a bit more torque. Any such issue will slow it down some.

_________________
Thomas


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 27 Dec 2021, 21:47 
Offline


User avatar
 Profile




Joined: 11/08/12
Posts: 12544
Post Likes: +5019
Location: Jackson, MS (KHKS)
Aircraft: 1961 Cessna 172
When you retest.

1) load it heavy as possible and try whatever takeoff config gives you the longest ground roll

2) do speed runs at low, Middle and high altitudes

3) do a vy climb and note results


I suspect the end result will be a borescope but unless it’s instrumentation the possibilities are power and drag. Above might help determine which


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 28 Dec 2021, 00:56 
Offline


 Profile




Joined: 01/17/21
Posts: 49
Post Likes: +24
Aircraft: C550
Had a K model with -6 engine’s & consistently got 270 to 275 true in the low 20’s .


Top

 Post subject: Re: MU2 Pre-buy speed 36 ktas below book
PostPosted: 28 Dec 2021, 02:42 
Offline


User avatar
 Profile




Joined: 06/02/15
Posts: 1896
Post Likes: +1106
Location: Fresno, CA (KFAT)
Aircraft: "Barren"
Username Protected wrote:
When you retest.

1) load it heavy as possible and try whatever takeoff config gives you the longest ground roll

2) do speed runs at low, Middle and high altitudes

3) do a vy climb and note results


I suspect the end result will be a borescope but unless it’s instrumentation the possibilities are power and drag. Above might help determine which


If the engine(s) are the problem, would TQ, ITT, FF, and Ng not make book?

_________________
Tom DeWitt
Previous: C172/C182/T210M/TBM850
APS 2004


Top

Display posts from previous:  Sort by  
Reply to topic  [ 91 posts ]  Go to page Previous  1, 2, 3, 4, 5 ... 7  Next




You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

Terms of Service | Forum FAQ | Contact Us

BeechTalk, LLC is the quintessential Beechcraft Owners & Pilots Group providing a forum for the discussion of technical, practical, and entertaining issues relating to all Beech aircraft. These include the Bonanza (both V-tail and straight-tail models), Baron, Debonair, Duke, Twin Bonanza, King Air, Sierra, Skipper, Sport, Sundowner, Musketeer, Travel Air, Starship, Queen Air, BeechJet, and Premier lines of airplanes, turboprops, and turbojets.

BeechTalk, LLC is not affiliated or endorsed by the Beechcraft Corporation, its subsidiaries, or affiliates. Beechcraft™, King Air™, and Travel Air™ are the registered trademarks of the Beechcraft Corporation.

Copyright© BeechTalk, LLC 2007-2022

.Genesys_85x50.jpg.
.instar.jpg.
.sierratrax-85x50.png.
.shortnnumbers-85x100.png.
.camguard.jpg.
.garmin-85x200-2021-11-22.jpg.
.gallagher_85x50.jpg.
.Davis_Aviation_85x50.jpg.
.saint-85x50.jpg.
.airpower-85x50.jpg.
.MountainAirframe.jpg.
.jetacq-85x50.jpg.
.EagleFuelCellsTriple.jpg.
.CiESVer2.jpg.
.bpt-85x50-2019-07-27.jpg.
.Rocky-Mountain-Turbine-85x100.jpg.
.kingairacademy-85x100.png.
.avfab-85x50-2018-12-04.png.
.ABS-85x100.jpg.
.Wentworth_85x100.JPG.
.ssv-85x50.jpg.
.jandsaviation-85x50.jpg.
.jetshades-85x150.png.
.AAI.jpg.
.avionwealth-85x50.png.
.tat-85x100.png.
.planelogix-85x100-2015-04-15.jpg.
.avionicssource-85x50.jpg.
.xnaut-85x50.jpg.
.tempest.jpg.
.wilco-85x100.png.
.wat-85x50.jpg.
.temple-85x100-2015-02-23.jpg.
.aopa-85x150-2022-06-16.png.
.blr-85x200.jpg.
.airmart-85x150.png.
.pdi-85x50.jpg.
.Latitude.jpg.
.aviationdesigndouble.jpg.
.nexus-85x50.jpg.
.Foreflight_85x50_color.png.
.blackhawk-85x100-2019-09-25.jpg.
.SCA.jpg.
.stanmusikame-85x50.jpg.
.dshannon.jpg.
.concorde.jpg.
.bkool-85x50-2014-08-04.jpg.
.aircraftassociates-85x50.png.
.dbm.jpg.
.cav-85x50.jpg.
.traceaviation-85x150.png.
.forge-85x50.jpg.
.ei-85x150.jpg.
.blackwell-85x50.png.
.echelon-85x50.png.
.ps_engineering.gif.
.geebee-85x50.jpg.
.Marsh.jpg.
.STLAir_85x50.jpg.
.komn-85x50.png.
.KalAir_Black.jpg.
.centex-85x50.jpg.
.kadex-85x50.jpg.
.chairmanaviation-85x50.jpg.
.greenwich-85x50-2020-08-10.jpg.