banner
banner

28 Mar 2024, 10:27 [ UTC - 5; DST ]


Concorde Battery (banner)



Reply to topic  [ 133 posts ]  Go to page Previous  1 ... 5, 6, 7, 8, 9  Next
Username Protected Message
 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 01:36 
Offline


User avatar
 Profile




Joined: 12/21/08
Posts: 929
Post Likes: +509
Location: Townsville (YBTL), Australia
Quote:
Uh, no, horsepower is horsepower. If both planes are making the same power at the same altitude, they’ll fly at the same speed.


My science brain is telling me, "That makes no sense"! :scratch:

_________________
Lee Fitzpatrick (aka Forkie!)


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 06:05 
Offline


User avatar
 Profile




Joined: 06/30/22
Posts: 1357
Post Likes: +716
Location: 0W3
Aircraft: Mooney 252/Encore
Tell that to Roy Lopresti.

Look what he did with the AA-5 series to make the Tiger/Cheetah. And the Mooney 201.

MAJOR speed gains without a power change.

And in the Mooney, a major part of that was cowling/cooling changes.


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 08:17 
Offline


User avatar
 Profile




Joined: 04/30/09
Posts: 1517
Post Likes: +859
Username Protected wrote:
I don't think that is clear. You see an airspeed change with cowl flaps even though the cross section changes very little. It does take aerodynamic power to cool a piston engine.


It is indeed a significant amount of lost energy. On the 414, I get a pitch change with the four cowl flaps opening and closing.

Imagine if there was a powerplant so efficient, it required almost no cooling system? Almost no power lost to cooling drag? No Tetraethyl Lead required? No fossil fuels required?

_________________
Former Taco Chef
Now - Battery Salesman
No Engineering Skills
I don’t know what I don’t know


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 08:23 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
Username Protected wrote:
Uh, no, horsepower is horsepower. If both planes are making the same power at the same altitude, they’ll fly at the same speed.

A nose redesign to package a turbine probably won’t buy much, as the cross-sectional area of the fuselage isn’t changing, the airframe wetted area is probably identical, and exhausting the turbine to the free stream might actually increase drag.

This is not correct at all. The IO-550R conversion that is done on a Bonanza for example uses a cowl that has much smaller openings for cooling air. Typically a V-tail Bo will cruise around 170 ktas. A similarly equipped V-tail will be 15-20 ktas faster with the IO-550R setup because of the reduced drag.

I have real world experience with this. I had a V-tail that I converted that flew 168 ktas before and 184 ktas after the IO-550R conversion (would have been closer to 190 ktas if I didn't have tip tanks). The IO-550R is only rated 10 hp more than the IO-550.

A turbine cowl is much more streamline than a piston cowl.

This article by David Rogers explains it.

https://www.nar-associates.com/technica ... screen.pdf


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 08:46 
Offline


User avatar
 Profile




Joined: 02/27/08
Posts: 3167
Post Likes: +1251
Location: Galveston, TX
Aircraft: Malibu PA46-310P
Username Protected wrote:
Uh, no, horsepower is horsepower. If both planes are making the same power at the same altitude, they’ll fly at the same speed.

A nose redesign to package a turbine probably won’t buy much, as the cross-sectional area of the fuselage isn’t changing, the airframe wetted area is probably identical, and exhausting the turbine to the free stream might actually increase drag.

This is not correct at all. The IO-550R conversion that is done on a Bonanza for example uses a cowl that has much smaller openings for cooling air. Typically a V-tail Bo will cruise around 170 ktas. A similarly equipped V-tail will be 15-20 ktas faster with the IO-550R setup because of the reduced drag.

I have real world experience with this. I had a V-tail that I converted that flew 168 ktas before and 184 ktas after the IO-550R conversion (would have been closer to 190 ktas if I didn't have tip tanks). The IO-550R is only rated 10 hp more than the IO-550.

A turbine cowl is much more streamline than a piston cowl.

This article by David Rogers explains it.

https://www.nar-associates.com/technica ... screen.pdf


Those speeds seem off. My io520 V35B was between 170-172 knots. I thought the 550 variants easily hit 180kts. At least thats what I read on the "Should I get the 550" threads.
Kevin

Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 09:49 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
Username Protected wrote:
This is not correct at all. The IO-550R conversion that is done on a Bonanza for example uses a cowl that has much smaller openings for cooling air. Typically a V-tail Bo will cruise around 170 ktas. A similarly equipped V-tail will be 15-20 ktas faster with the IO-550R setup because of the reduced drag.

I have real world experience with this. I had a V-tail that I converted that flew 168 ktas before and 184 ktas after the IO-550R conversion (would have been closer to 190 ktas if I didn't have tip tanks). The IO-550R is only rated 10 hp more than the IO-550.

A turbine cowl is much more streamline than a piston cowl.

This article by David Rogers explains it.

https://www.nar-associates.com/technica ... screen.pdf


Those speeds seem off. My io520 V35B was between 170-172 knots. I thought the 550 variants easily hit 180kts. At least thats what I read on the "Should I get the 550" threads.
Kevin

Truth be told, my plane originally had an IO-520. However, my dad's V-tail, same model as mine, no tip tanks and had IO-550B would only cruise at 168 ktas.

Your IO-520 was 4 kts faster than mine. If you don't have tip tanks, then that makes sense because I did have them. My dad's IO-550 plane had a McCauley 3-bladed prop. If he had a Hartzell he probably would have been in the 173 kts range.

The one IO-550R plane I flew in that didn't have tip tanks flew 190 ktas.

Last edited on 28 Jul 2022, 10:24, edited 4 times in total.

Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 10:07 
Offline


User avatar
 Profile




Joined: 08/14/13
Posts: 6055
Post Likes: +4628
Username Protected wrote:
Those speeds seem off. My io520 V35B was between 170-172 knots. I thought the 550 variants easily hit 180kts. At least thats what I read on the "Should I get the 550" threads.
Kevin


6% more displacement gives you ~5% more speed? Fascinating departure from reality id wager


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 10:59 
Offline


 Profile




Joined: 01/06/08
Posts: 4665
Post Likes: +2678
Aircraft: B55 P2
Comparing airspeeds between different planes is not easy. ASIs are not all that well calibrated - the two on my plane disagree by ~3 knots at 160 IAS. Then some tachs are not well calibrated so one person may be at 2500 rpms, the other at 2550. Rigging can be different. Different antennas, engine baffles. Some cowl flaps don't close completely.

Then of course updrafts can make a big difference in cruise speed. Unless the air is very smooth its not uncommon to see a few knots variation. (and most pilots tend to notice the high numbers).

It is possible to do a careful measurement, but most people are too lazy to actually do it (myself included)

All that said, having ownd a IO520 baron and a IO550 baron with similar weights, the 550 performance advantage (climb and cruise) "seems" substantially more than the difference in displacement would imply.


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 14:28 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
Username Protected wrote:
Comparing airspeeds between different planes is not easy. ASIs are not all that well calibrated - the two on my plane disagree by ~3 knots at 160 IAS. Then some tachs are not well calibrated so one person may be at 2500 rpms, the other at 2550. Rigging can be different. Different antennas, engine baffles. Some cowl flaps don't close completely.

Then of course updrafts can make a big difference in cruise speed. Unless the air is very smooth its not uncommon to see a few knots variation. (and most pilots tend to notice the high numbers).

It is possible to do a careful measurement, but most people are too lazy to actually do it (myself included)

All that said, having ownd a IO520 baron and a IO550 baron with similar weights, the 550 performance advantage (climb and cruise) "seems" substantially more than the difference in displacement would imply.

Yes this is all very true. That's why I don't compare airspeeds on planes I fly unless I do GPS testing. Fly a box and find the true TAS.


Top

 Post subject: Re: Low cost turbine....
PostPosted: 28 Jul 2022, 16:04 
Online


 Profile




Joined: 12/24/18
Posts: 476
Post Likes: +472
Location: KHFD
Aircraft: F33A
Username Protected wrote:
Uh, no, horsepower is horsepower. If both planes are making the same power at the same altitude, they’ll fly at the same speed.

A nose redesign to package a turbine probably won’t buy much, as the cross-sectional area of the fuselage isn’t changing, the airframe wetted area is probably identical, and exhausting the turbine to the free stream might actually increase drag.

Two words: "cooling drag".

A significant amount of power is being used to push air through the piston engine for cooling. That is why some setups have cowl flaps, to reduce that drag.

The turbine also has jet thrust. Typically, this is about 10% of the power output, so the effective horsepower is 10% larger when the shaft horsepower is the same.

For any given shaft horsepower, the turbine airplane has much lower drag and higher effective output power.

Mike C.

In theory you are all correct - however, I've been on the design end of this problem, and it doesn't buy much. Yes, a turboprop adds some jet exhaust (assuming you can duct it properly), but the re-packaging of the nose isn't going to get you as much as you think. The extended length required for the turboprop and exhaust will increaser fineness ratio of the airframe, but you'll still have a very similar installation as the reduction gearbox (on either a PT6,TPE331, or Allison 250) is in the same cross-sectional ballpark (vertically) as a IO-550 (horizontally). And yes, cooling drag might be lower if the inlet is properly tailored, but you still need airflow around the turboprop to ensure radiant heat doesn't cook the harnesses, coke the fuel lines, and destroy the sensors.

Oh, and Roy Lopresti did some great work on Mooneys, mostly cleaning up the sloppiness in the original design. Not a lot of magic - just attention to detail.

Top

 Post subject: Re: Low cost turbine....
PostPosted: 29 Jul 2022, 09:18 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
Username Protected wrote:
In theory you are all correct - however, I've been on the design end of this problem, and it doesn't buy much. Yes, a turboprop adds some jet exhaust (assuming you can duct it properly), but the re-packaging of the nose isn't going to get you as much as you think. The extended length required for the turboprop and exhaust will increaser fineness ratio of the airframe, but you'll still have a very similar installation as the reduction gearbox (on either a PT6,TPE331, or Allison 250) is in the same cross-sectional ballpark (vertically) as a IO-550 (horizontally). And yes, cooling drag might be lower if the inlet is properly tailored, but you still need airflow around the turboprop to ensure radiant heat doesn't cook the harnesses, coke the fuel lines, and destroy the sensors.

Oh, and Roy Lopresti did some great work on Mooneys, mostly cleaning up the sloppiness in the original design. Not a lot of magic - just attention to detail.

What I know from my experience with the Evolution was that it is quite easy to predict what your TAS will be based on the HP you are producing (within a given rage). They had tried to install a piston on the Evo and had estimates on speeds for that as well. Those estimates fell short. It was explained to me that it was due to the extra drag of the larger nose to fit the piston, since everything else was equal. Would you suggest something different?

If I remember correctly they said the piston Evo was going to cruise at 260-270 ktas and the real world speeds were under 240 ktas.


Top

 Post subject: Re: Low cost turbine....
PostPosted: 29 Jul 2022, 09:56 
Online


User avatar
 Profile




Joined: 08/12/08
Posts: 7399
Post Likes: +2224
Company: Retired
Location: Santa Barbara, CA
Aircraft: '76 A36 TAT TN 550
Username Protected wrote:
The one IO-550R plane I flew in that didn't have tip tanks flew 190 ktas.

A V35 with an IO-520 (if memory serves) has a book cruise speed of 176 knots.

Throw in an IO-550 and I think that goes to 180 KTAS.

My experience with Beech products tells me book airspeeds can often be exceeded (and they can be flown at lighter than gross weight which also helps them go faster). My IA has a V35 on which he routinely sees 184 KTAS.

So could an IO-550R see 190 KTAS?

I think it’s possible. But I don’t feel as though it is a massive improvement over what a well rigged V35 can do with an IO-550B.

For the extra cost I’d rather have a TAT TN vs the 550-R.

With a TAT TN 550 in my A36 we see 185 KTAS all day every day at 12,000’.

If we go higher we get an easy 195 KTAS at 17,000’ on 15.x GPH.

With any kind of tailwind we’re well over 200 knots groundspeed. I saw 247 knots going east earlier this year. It makes a big difference when you’re going from CA to FL.
:thumbup:

_________________
ABS Life Member


Top

 Post subject: Re: Low cost turbine....
PostPosted: 29 Jul 2022, 10:09 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
Username Protected wrote:
The one IO-550R plane I flew in that didn't have tip tanks flew 190 ktas.

A V35 with an IO-520 (if memory serves) has a book cruise speed of 176 knots.

Throw in an IO-550 and I think that goes to 180 KTAS.

My experience with Beech products tells me book airspeeds can often be exceeded (and they can be flown at lighter than gross weight which also helps them go faster). My IA has a V35 on which he routinely sees 184 KTAS.

So could an IO-550R see 190 KTAS?

I think it’s possible. But I don’t feel as though it is a massive improvement over what a well rigged V35 can do with an IO-550B.

For the extra cost I’d rather have a TAT TN vs the 550-R.

With a TAT TN 550 in my A36 we see 185 KTAS all day every day at 12,000’.

If we go higher we get an easy 195 KTAS at 17,000’ on 15.x GPH.

With any kind of tailwind we’re well over 200 knots groundspeed. I saw 247 knots going east earlier this year. It makes a big difference when you’re going from CA to FL.
:thumbup:

As I said, the V35 that we owned with an IO-550B flies 168 ktas.

As far as the IO-550R plane flying 190 ktas. It does. I flew it. It was impressive how fast it climbed and how fast it flew at 10k.

I have heard there are some IO-550R planes that fly over 200 ktas. Perhaps they found someone that is good with rigging like you mentioned for IO-550B planes. Don't know.

The other benefit of the IO-550R setup vs the IO-550B as well as a TN plane is that you have much cooler cylinder head temps and have a longer TBO.

The A36 with the IO-550R flies 185 ktas with no tip tanks. (At least that is what is reported, I have not flown in one)

IO-550B overhaul schedule is 1700 hours
IO-550R overhaul schedule is 2000 hours

The IO-550R conversion also moves your CG forward a couple inches.

I have also heard that at overhaul of the IO-550R that there is less wear and tear.

Last edited on 29 Jul 2022, 11:58, edited 1 time in total.

Top

 Post subject: Re: Low cost turbine....
PostPosted: 29 Jul 2022, 11:27 
Offline


 Profile




Joined: 08/22/12
Posts: 518
Post Likes: +270
This is the first I've heard of the IO-550R. I'm intrigued. When our IO-550B needs overhaul I may consider this option. What does the package cost to do?


Top

 Post subject: Re: Low cost turbine....
PostPosted: 29 Jul 2022, 11:56 
Offline


User avatar
 Profile




Joined: 12/17/10
Posts: 1611
Post Likes: +272
Location: Valparaiso, IN
Aircraft: Lancair Evolution
Username Protected wrote:
This is the first I've heard of the IO-550R. I'm intrigued. When our IO-550B needs overhaul I may consider this option. What does the package cost to do?

It's EXPENSIVE. Worth it IMO if you plan to keep the plane, but it costs $170,000 right now. The reason it's so expensive is because you get an entire new front end. Engine, cowling (upper and lower), lighting, prop, etc. I forgot to mention that it moves your CG forward some too. Pretty much the same amount adding a TN does.

It used to be done by Atlantic Aero but it was bought by Summit Aviation. The guy that I bought mine from is still working there. His name is John Ackerman. Great guy.

https://summitaviationmfg.com/io550/


Top

Display posts from previous:  Sort by  
Reply to topic  [ 133 posts ]  Go to page Previous  1 ... 5, 6, 7, 8, 9  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 2007-2024

.aviationdesigndouble.jpg.
.shortnnumbers-85x100.png.
.cav-85x50.jpg.
.AAI.jpg.
.aeroled-85x50-2022-12-06.jpg.
.Foreflight_85x50_color.png.
.ssv-85x50-2023-12-17.jpg.
.temple-85x100-2015-02-23.jpg.
.sierratrax-85x50.png.
.planelogix-85x100-2015-04-15.jpg.
.CiESVer2.jpg.
.chairmanaviation-85x50.jpg.
.traceaviation-85x150.png.
.jetacq-85x50.jpg.
.saint-85x50.jpg.
.concorde.jpg.
.kadex-85x50.jpg.
.blackwell-85x50.png.
.bullardaviation-85x50-2.jpg.
.midwest2.jpg.
.MountainAirframe.jpg.
.tat-85x100.png.
.wilco-85x100.png.
.Wingman 85x50.png.
.stanmusikame-85x50.jpg.
.blackhawk-85x100-2019-09-25.jpg.
.one-mile-up-85x100.png.
.Latitude.jpg.
.Genesys_85x50.jpg.
.pure-medical-85x150.png.
.gallagher_85x50.jpg.
.tempest.jpg.
.aircraftassociates-85x50.png.
.avfab-85x50-2018-12-04.png.
.ei-85x150.jpg.
.centex-85x50.jpg.
.jandsaviation-85x50.jpg.
.kingairacademy-85x100.png.
.geebee-85x50.jpg.
.bpt-85x50-2019-07-27.jpg.
.camguard.jpg.
.daytona.jpg.
.Wentworth_85x100.JPG.
.boomerang-85x50-2023-12-17.png.
.headsetsetc_Small_85x50.jpg.
.SCA.jpg.
.lucysaviation-85x50.png.
.airmart-85x150.png.
.dbm.jpg.
.Marsh.jpg.
.aircraftferry-85x50.jpg.
.Rocky-Mountain-Turbine-85x100.jpg.
.kingairnation-85x50.png.
.wat-85x50.jpg.
.ABS-85x100.jpg.
.pdi-85x50.jpg.
.avionwealth-85x50.png.