Push-Pull Configuration Tutorial: Very Fast Prop Plane

This video shows how to set up plane using center line forward-mounted tractor (pull) propellers and backward-mounted (pusher) propellers.

[@JimPlaysGames]

This is so cool! I love your attention to detail and the background on real world aircraft. Great stuff!

[@Echo3]

Thank you. It is a topic that I enjoy very much.

[@sethpurifoy6025]

That air intake as tail booms trick is just what I need for a twin-boom design! Of course, there’s also the bounty of prop tips here. Nice video :)

[@Echo3]

Thanks. The air intake is much lighter than the structural pieces, so it's pretty useful.

[@Nivz54]

Hey Echo, just found out about your channel and i wanna say that youre amazing and keep up the good work and interesting content 😊

[@Echo3]

Thank you very much. I intend to keep making videos.

[@R3dp055um]

Yes, yes, GOOD! Exactly what I was looking for, like a Cessna Skymaster. I personally took the stock Gull and made a twin engine electric out of it, but that was conventional twin engine config, not the Pushme-Pullyu. On the subject of leveling front/rear landing gear, do you ever have a problem with crazy bouncing when you hit Launch and it first appears on the runway? I haven't seen this in the last year, but it used to be a regular problem for me. Most excellent videos. Unlike some popular KZbinrs, you are actually *good* at explaining things. Liked, Subbed, and ding-ding bell click.

[@Echo3]

The crazy bouncing issue seems to happen if I overload the landing gear with too much weight. Sometimes playing with the spring strength and dampening can help, but that is also a good way to invite the Kraken. Thanks for the Sub!

[@ThalesMML]

Very good videos, I suggest PartAngleDisplay mod to see wing angle of incidence precisely when rotating.

[@rulingmoss5599]

This helped me make a very cool little prop, push pull config with 8 small propellers each and I intend to send it to duna. Thanks!

[@Echo3]

That is awesome!

[@andrewsad1]

I learn something new from every one of these videos

[@Echo3]

Thanks. Are there any topics that you'd like me to cover?

[@specialneedsmolester1957]

I have found some stuff that might be very obvious but could be useful for people who want to build props. I build my plane and use launch clamps to see the max horizontal lift the blades will produce then I multiply that number by how many blades there are. I use that number to set the max power on a motor. Always round up on that. This is useful to keep the torque and weight down and less electric drain.

[@Echo3]

This sounds useful!

[@Hohor6153]

For who wonder about Delta-v like me i just look how much engines burn, it was 0.3 at total so with 190 unit of fuel you have 633 second of thrust lets say some of that for take of and landing you have solid 10 minute of thrust independent of your throttle. With 270 meters per second speed and 600 second long fly you can reach 162 kilometers away. But i just did fly towards to west and reach the shores with burning 150 fuel and 40 left. its 147 km away and there is mountain in between, i climb to over 5km. You can easily reach and unlock Cove Launch site (47km) and İsland Airfield (32km).

[@leo_puck]

what a good video!!

[@Echo3]

Thanks!

[@orangekitty8974]

Nice plane!

[@Echo3]

Thank you very much. I had been working on making a fast prop plane, and this is the design I settled on.

[@egggrenade2746]

No torque rotation is a actual dream

[@billcroft449]

Hello, I would like to know where the information on the advantages and disadvantages of the push-pull configuration comes from? I also want to know how to find the information related to the design of the front and rear power systems?

[@Echo3]

Some of the advantages only apply to real life as KSP doesn't consider fluid dynamics in its physics model. But as far as Newtonian physics it does. This opposite rotation of the propellers cancels the torque and makes the plan very stable and easy to fly. I don't remember what all sources I used as I did a lot of research about prop planes and helicopters. I know I also asked a lot of questions to my friends that are actual pilots.

[@billcroft449]

Thanks for your answer. I would also like to ask you whether there is any additional vibration problem with the rear engine in the push-pull configuration. If so, is there any literature on how to solve this problem? And whether the efficiency of the rear propeller is disturbed by the airflow through the front propeller, causing it to decrease? Finally, are there any design solutions or design difficulties related to the intake and exhaust of the push-pull engine?

[@Echo3]

@@billcroft449 I know I read up on a lot of this before making the video. Unfortunately, I'm not recalling all of it. I believe there were some slight issues with efficiency with the rear props due to the airflow around the fuselage - maybe it was about 80%. I don't recall reading about any issues with the intake or exhaust. Some advantages I remember were that it didn't have the noise issue that a typical contra-rotating prop design has, but it still cancels out the torque. And there isn't an off center thrust issue due to the loss of an engine. Rear mounted props were a liability early on in aviation as it was very dangerous for a pilot trying to bail out. But with an ejection seat, this wouldn't be a problem.

[@billcroft449]

@@Echo3 Thank you for your explanation

[@qui-gontimtherandomraptor1072]

May I ask why you don't share the craft files for these? These are awesome builds!!!

[@Echo3]

Mostly it's because I don't remember. I've been getting better at it though. I have been uploading to KerbalX.

[@TeenWithACarrotIDK]

I think France made a bomber that had double push/pull engines, but I don’t know if it actually entered battle or not.

[@Echo3]

You might be thinking of the Farman F.220

[@leedleleedleleedlelee6825]

i have a question is the deploy angle need for this to work cuz im on xbox and there is no deploy angle option for some reason a couple of options are missing but just the ones that are not necessary to get into space.

[@Echo3]

For the propeller blades, I think consol uses the term authority limit. That gets bound to the KAL 1000.

[@leedleleedleleedlelee6825]

Oh ok

[@leedleleedleleedlelee6825]

@@Echo3 I got it mostly working to fly's I have to play with RPM limit controls to get it airborne but after that I got it to stay in the air I don't know why but mine is slower even though I fallowed every step mine topped out at 121 MPS or 435 KPH / 270 MPH I'm not vary good with propellers but it flies better than my last attempt and look better too so thanks for the help

[@Echo3]

@@leedleleedleleedlelee6825 I did make another video to help players get started with propellers. It is not nearly as complex. kzbin.info/www/bejne/m369hJypl81_bKM

[@normalhuman9260]

​@@leedleleedleleedlelee6825you can still do it the same way as he did in this video. Use a quick command to turn on engine,another to max rpm and torque,then binde Kal to main throttle and have the Kal adjust the authority limit on the blade deployment. Just remember to set the propellers to deploy while building so that the Kal will actually work. You also have an option on xbox when binding the Kal to main throttle,you can chose "Incremental or Absolute" authority. Use absolute and just hold LB when slightly adjusting the throttle. I'm sure you've already figured all this out by now,I'm just saying it incase someone else is reading this and wondering the same thing. I only play on console so I've had to learn how they differ and how to make it work on console. All the best to both of you.

[@AveriV1]

what mods do u use

[@Echo3]

The mods in this video are only visual and informative. Spectra, scatterer, waterfall, parallel, distant object enhancement, particle reentry effects, TUFX, texture replacer, Kerbal Engineer, RCS build aid.

[@Timroin]

what mod?

[@Echo3]

The craft is all stock + DLC. I used Spectra, Scatterer and parallax for the graphics. Kerbal Engineer and RCS Build Aid were used to help design the craft.

[@pipez_7595]

Just wanna know, is this used in real life?

[@CaptainBDSC]

Yes, that's what he says in the video.

[@CaptainBDSC]

en.m.wikipedia.org/wiki/Push-pull_configuration

[@Echo3]

It is not a common design, but concept has been in the works since WWI.

[@Duckfisher0222]

the sound is off, makes it very hard to follow the tutorial if you are doing it first then explain that step while you are already doing the 2nd step.