Results 1 to 29 of 29

Thread: Engines. A Discussion.

  1. #1

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like

    Engines. A Discussion.

    Preface. I'm a believer in no replacement for displacement. Juice up a 320, a 360 still beats it. In a given displacement you can maximize fuel supply, induction, compression, and ignition but with typical opposed direct drive engine RPMs we hit a wall for max power output.

    Enter the Highlanders using Yamaha's turbo Apex motor. RPMs up near 10K and gear reduction driving lightweight props. Reportedly running 300hp in a very compact and lightweight package. So far I've only seen this engine in very lightweight airplanes.

    The question. Would that motor-prop combo provide good performance in heavier airframes? Would it run circles around my maximized IO-390 or does opposed-direct drive grunt spinning a beefier prop pull a heavier plane better? Is 300hp always 300hp? How about an Apex powered 185? Anyone have any wisdom to offer?
    Thanks CharlieN, Olibuilt, Lance2050 thanked for this post

  2. #2

    Join Date
    Mar 2016
    Location
    Down low in the hills of Vermont USA
    Posts
    1,241
    Post Thanks / Like
    BMEP is a huge player in making power and is something lacking in the antique cylinder design in aircraft engines.

  3. #3

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    I'm from the muscle car generation. These days while I'm not a fan of the noise I am impressed by the new generation's rice rocket performance cars. But I don't see anyone dropping a piped-up Subaru motor into a Camaro chassis. There's a disconnect in my mind between the small displacement/high output engines and bigger heavier vehicles but I'm not sure why. I've had a few Yamaha 4-stroke sowgos and one outboard. Impressive engines, no question. Application of that power is part of the question. A V belt transmission allows my snowgo engine to run in the power band at all speeds. A fixed pitch prop? Interesting stuff. I hope to see more Apex powered airframes.

    Horsepower equals torque multiplied by rpm, divided by a constant. Because there is generally a limit on how fast you can spin an engine, having higher torque allows for greater horsepower at lower rpms.
    Last edited by stewartb; 02-22-2020 at 12:54 PM.

  4. #4

    Join Date
    Mar 2016
    Location
    Down low in the hills of Vermont USA
    Posts
    1,241
    Post Thanks / Like
    I would love to see how a modern sled motor would be with it's belt transmission used in a plane. I fully expect belt life would snub that project quick though but then I do not have direct knowledge of these newest sleds. Either the new 2 smokes or the 4 strokes would be interesting with a fixed pitch and variable belt reduction.
    Today's outboard motors are incredible, even my old 2.6 Yamaha Excel with 250ish HP and still has monstrous torque down low. And it is still economical on fuel burn. Packaging on the new motors may not be all that tough since they are all injected and dry sump, or call it remote sump oil re-packaging is not that tough.

    In time I expect I will have a mid size 4 cyl car engine prepped for my plane, not a Subi motor. It will offer about 250+ ft Lbs down at 2500 crank with well over 300 Hp all over the place.
    With a 2.3 reduction that works out in the range of 575 Ft Lbs at 1100 revs at the prop. That is 6 cyl power at big 4 cyl weight. Probably enough torque to be impressive with fixed pitch. Fuel burn at cruise will be easy on the wallet. That is on Mogas as well.
    I expect I will be utilizing a ground adjustable but need to see what the market offers at that time.
    Likes stewartb, Lance2050 liked this post

  5. #5

    Join Date
    Sep 2003
    Posts
    6,952
    Post Thanks / Like
    At least one self launching glider uses a tooth belt to drive the prop.

  6. #6
    mvivion's Avatar
    Join Date
    Jun 2003
    Location
    Bozeman,MT
    Posts
    10,732
    Post Thanks / Like
    I'd be leery of any aircraft engine using an untested gear box. Lots of examples of gear boxes causing problems in aircraft.

    Belts in aircraft?? Look no further than the Robinson helicopters.....

    MTV

  7. #7

    Join Date
    Mar 2016
    Location
    Down low in the hills of Vermont USA
    Posts
    1,241
    Post Thanks / Like
    The belt I am interested in is this,
    https://www.continental-industry.com...NTI-SILENTSYNC

    Lets see if that link will work

  8. #8

    Join Date
    Mar 2016
    Location
    Down low in the hills of Vermont USA
    Posts
    1,241
    Post Thanks / Like
    On aircraft engines, I would love to see someone produce cylinder heads with D shape intake ports.
    It is common to raise the floor of the port with epoxy creating a much better short side radius which would in ant plane motor greatly enhance cylinder fill.
    Sure works in older bike and car motors. But every once in awhile when one goes in to inspect things the epoxy is no longer there. Never hurt anything but it just is not there.
    But no matter what you do you can not fix a combustion chamber that is 80 years beyond it's engineering cycle. I am somewhat scared to improve cylinder fill unless you can improve mixture distribution so the engine does not break itself.

  9. #9
    Olibuilt's Avatar
    Join Date
    Nov 2009
    Location
    Montreal, Canada
    Posts
    824
    Post Thanks / Like
    Innovation is awesome. But can a ''300hp'' Yamaha turn a 90'' McCauley prop like a good old Lycoming??

  10. #10

    Join Date
    Mar 2016
    Location
    Down low in the hills of Vermont USA
    Posts
    1,241
    Post Thanks / Like
    Need to gear it for the task. A McCauley might not be my first choice though. I have not run the numbers to see if it would be logical.
    That Yamaha is not a Big Torque motor although boost makes up for lack of natural torque.
    Years back there was an engine block for the Hayabusa to run without the gearbox. If that were simplified for aviation use and the engine built to a 1600CC it would be impressive.
    I run a turbo Busa motor in one of my cars, being the car is under #800 and with just 11# boost it has an easy 320+ Hp with monstrous torque from 2000 to 10500. Car could torque up hills at 1300rpm in top gear. That engine is stock, no reduced compression, nothing. Just some stiffer clutch springs. Great engines.

  11. #11
    CamTom12's Avatar
    Join Date
    Jul 2015
    Location
    Huntsville, AL
    Posts
    740
    Post Thanks / Like

    Engines. A Discussion.

    Quote Originally Posted by Olibuilt View Post
    Innovation is awesome. But can a ''300hp'' Yamaha turn a 90'' McCauley prop like a good old Lycoming??
    Charlie’s already made the point, but yes.

    You’d have to add a reduction drive, but 300hp is 300hp. The RPM that power is made at only matters for the gearing required to get it to the ground (or to the prop, in this case).

    On a PowerStroke forum a while back there was a great discussion about this, complete with math. The bottom line is that a 400hp v8 gas engine (when properly geared) can pull a load up a mountain equally as well as a 400hp diesel.

  12. #12

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    Wow. On that point? Disagree. I've had several GMC pickups with a few different engines and there's no way a gas engine pulls like a diesel of the same HP class. No way. I currently drive a big V8 gas truck after a couple of Duramax trucks. Hook up a heavy trailer? No comparison.

    Put that into context for the Yamaha Apex? My SkiDoo Etecs are awesome sleds but they suck hind tit for torque and power compared to my Yamaha. In the snowgo example the Yamahas are HEAVY. That comes into play with sleds as much as airplanes. Go back to the Duramax? Torque conquers weight. And the confusion continues!
    Last edited by stewartb; 02-22-2020 at 11:07 PM.

  13. #13
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,508
    Post Thanks / Like
    Some "ifs". If the "actual", not necessarily "claimed" horsepower is the same, and if they are both at their max HP RPM, and if the atmospherics and tires and such are the same, and the towing vehicle is the same gearing and weight, they would pull the same trailer the same speed up the same hill. But those are a lot of "ifs", so comparison can be deceptive. Cam Tom is right - horsepower is horsepower. 550 ft-lb per sec.

    Edit: Here's a funny. Years ago I decided to measure the power required to pull a horse-drawn sickle-bar hay mower, like in my avatar. So I carefully measured the tension in the harness traces and the horses' speed, and guess what? 2 HP to pull that mower. Pretty cool, I thought.
    Last edited by Gordon Misch; 02-22-2020 at 11:14 PM.
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)
    Likes alaskadrifter liked this post

  14. #14

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    Not many Peterbilts running 6.0 Chevy gas engines. Go figure.

  15. #15
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,508
    Post Thanks / Like
    Lots of reasons. None of which refute Charlie's and Tom's and my statements. Yawn.
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)

  16. #16

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    And clearly you've never driver a gas vs equal diesel. Yawn is right. But this topic is about airplanes. High revving snowgo engine vs bigger displacement and slower revving airplane engines. Pickup trucks are the epitome of yawn.

  17. #17
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,508
    Post Thanks / Like
    Both, all of the Big Three manufacturers for 50 years. Horsepower is horsepower. Period. If you don't like that you shouldn't have asked. Good evening, sir.
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)

  18. #18
    CamTom12's Avatar
    Join Date
    Jul 2015
    Location
    Huntsville, AL
    Posts
    740
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Wow. On that point? Disagree. I've had several GMC pickups with a few different engines and there's no way a gas engine pulls like a diesel of the same HP class. No way. I currently drive a big V8 gas truck after a couple of Duramax trucks. Hook up a heavy trailer? No comparison.

    Put that into context for the Yamaha Apex? My SkiDoo Etecs are awesome sleds but they suck hind tit for torque and power compared to my Yamaha. In the snowgo example the Yamahas are HEAVY. That comes into play with sleds as much as airplanes. Go back to the Duramax? Torque conquers weight. And the confusion continues!
    Here’s the problem - you’ve got to optimize the gearing to take advantage of the power where it’s made.

    I don’t prefer to hang out behind an engine “screaming” at 5k+ rpms while climbing a hill. I much preferred my last SuperDuty’s easy 2k-ish rpms. That’s why I owned that truck and not a gasser.

    But, the truth remains that if two engines make identical power (and are optimally geared for that power band), they’ll perform identically. Regardless of what RPM that power is made at.

    Personal preference doesn’t change the math.
    Likes Steve Pierce liked this post

  19. #19

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    Like I said earlier.... application. Back to airplanes, please?

  20. #20
    CamTom12's Avatar
    Join Date
    Jul 2015
    Location
    Huntsville, AL
    Posts
    740
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Like I said earlier.... application. Back to airplanes, please?
    Yeah, so here we are. Talking about the application of power to do work.

    Back to asking if 300hp can spin a prop the same way as 300hp can spin a prop.

    Here’s where I say again: yes, it can.
    Likes Gordon Misch liked this post

  21. #21

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    On my planes the prop is what does the important work. I'm guessing the Apex motor and reduction drive have limitations for prop weight. That's probably a deal breaker for heavier airplanes. Especially where a constant speed is desired. I'm curious about the Apex and reduction for Cub types. I haven't seen or heard of one and that surprises me. Somebody must be trying it. If anyone here has some hands-on experience I'd like to talk.

    Side note, Mike Patey's engine and prop choices on his new Cub are very interesting in the context of this topic.
    Last edited by stewartb; 02-23-2020 at 01:40 PM.

  22. #22
    CamTom12's Avatar
    Join Date
    Jul 2015
    Location
    Huntsville, AL
    Posts
    740
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    On my planes the prop is what does the important work. I'm guessing the Apex motor and reduction drive have limitations for prop weight. That's probably a deal breaker for heavier airplanes. Especially where a constant speed is desired. I'm curious about the Apex and reduction for Cub types. I haven't seen or heard of one and that surprises me. Somebody must be trying it. If anyone here has some hands-on experience I'd like to talk.
    Now that’s a good point. I don’t know the limits for the current reduction drive, but if they’re not up to spec then I don’t know why a beefier one couldn’t be engineered/built.

    I’m not personally aware of any reduction drives that can take hydraulic CS props. There must be some out there though. Wasn’t the guy building the Raptor canard plane using a 300-something hp diesel car engine and a hydraulic CS prop?

    Direct drive is simpler, and that’s why I’ll probably always use it. But 300hp is 300hp once you get it geared right.

    Quote Originally Posted by stewartb View Post
    Side note, Mike Patey's engine and prop choices on his new Cub are very interesting in the context of this topic.
    True, but it helps to have an engine like that just sitting around the shop. Especially if the context of the build was to use scrap or previously used parts.

  23. #23
    MN_flyer1's Avatar
    Join Date
    Jan 2012
    Location
    Hutchinson, MN
    Posts
    107
    Post Thanks / Like
    Balance is the challenge. A large diameter, slow prop is more efficient. The challenge is to match the engine HP to the RPM range the prop is most efficient. We used to have a Pawnee Brave (Ag Plane) that had a Continental Tiara engine. The prop turned 1/2 engine speed. Engine was 285 HP at 4000 RPM (406 cu in). Was very quiet and smooth running since the prop was turning slow. Way quieter than the Ag Wagon with the IO-520 (520 cu in).

    https://en.wikipedia.org/wiki/Continental_Tiara_series
    Likes CamTom12 liked this post

  24. #24
    mvivion's Avatar
    Join Date
    Jun 2003
    Location
    Bozeman,MT
    Posts
    10,732
    Post Thanks / Like
    Quote Originally Posted by CamTom12 View Post
    I’m not personally aware of any reduction drives that can take hydraulic CS props. There must be some out there though.
    Lycoming built lots of GO engines in that power range, all of which used CS props. How adaptable those gearboxes might be?? Who knows?

    MTV
    Likes CamTom12 liked this post

  25. #25
    CamTom12's Avatar
    Join Date
    Jul 2015
    Location
    Huntsville, AL
    Posts
    740
    Post Thanks / Like
    Quote Originally Posted by MN_flyer1 View Post
    Balance is the challenge. A large diameter, slow prop is more efficient. The challenge is to match the engine HP to the RPM range the prop is most efficient. We used to have a Pawnee Brave (Ag Plane) that had a Continental Tiara engine. The prop turned 1/2 engine speed. Engine was 285 HP at 4000 RPM (406 cu in). Was very quiet and smooth running since the prop was turning slow. Way quieter than the Ag Wagon with the IO-520 (520 cu in).

    https://en.wikipedia.org/wiki/Continental_Tiara_series
    Nice! Like running a turbine!

  26. #26

    Join Date
    Oct 2018
    Location
    Minot, ME
    Posts
    97
    Post Thanks / Like
    Interesting to think about. Plenty of guys getting over 200HP from skidoo 4 stroke turbocharged motor.

    It's lightweight.. BUT.. if you added the weight of the required gear reduction.... would it be that great of a package?

    Lots of money to find out. I love guys that like to spend money to find out. I'll sit here and watch, and dream.

    JP

  27. #27
    Cub Special Ed's Avatar
    Join Date
    Oct 2016
    Location
    MT/SD
    Posts
    467
    Post Thanks / Like
    Click image for larger version. 

Name:	1102112500-attachment.jpg 
Views:	37 
Size:	37.9 KB 
ID:	47256
    "There are 3 kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves." Will Rogers

  28. #28
    WWhunter's Avatar
    Join Date
    Aug 2003
    Location
    Laporte, Minnesota and the white sandy beaches of NW Florida
    Posts
    1,466
    Post Thanks / Like
    A friend recently got his Kitfox flying with a Yamaha RX-1 motor. He has Full Lotus floats on the plane. He de-tuned it slightly (I think he mentioned around 120-130HP). I was flying around his home the day of his trial flights and took some photos. He was taking off from a snow covered lake (MN in Dec. so frozen over), and I saw very good T/O performance. I thenk we will see a lot more of these engines flying soon. I actually bought one for one of my aircraft projects but ended up selling it due to the fact tht I already have too many projects!!!
    Likes stewartb liked this post

  29. #29

    Join Date
    Oct 2012
    Posts
    5,114
    Post Thanks / Like
    Here's a video about the gear box. The clutch is interesting. https://m.youtube.com/watch?v=0ks9LqboEeo

    I'm still curious about how mass plays into it. Mass of the prop as well as mass of the airplane.

Similar Threads

  1. Experimental: Dan's D&E Wings Discussion
    By Bugs66 in forum Experimental Cubs
    Replies: 31
    Last Post: 02-23-2017, 04:25 PM
  2. Coyote gun discussion (argument)
    By Fencer in forum Cafe Supercub
    Replies: 38
    Last Post: 02-16-2014, 07:59 AM
  3. ELT Discussion
    By StewartB in forum Cafe Supercub
    Replies: 5
    Last Post: 05-18-2011, 01:17 AM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •