Like a Lotus 7 with a LS Swap

I have mentioned here before I want a Learjet. Not just any Learjet, but specifically a 24XR. For a cool $300,000 you can fly in the most luxurious and amazing planes the 60/70's had to offer.

Sadly with the move from Turbojets to more quiet and efficient Turbofans, the old CJ610 was just too noisy for the US government to allow to fly here without the dumb Hush kits.


Let me tell you if you haven’t heard an un-hushed turbojet taking off, you are missing out on one of the best noises on earth. But they are loud and they are definitely no very fuel efficient. With takeoff the LJ24 uses about half its fuel in the first hour because thirsty boy.

So I always thought if I had “fuck you” money I would pay all the fee and fill out all the forms to upgrade the jets to more modern turbofans. BUt which ones would I go with? Well today ladies and germs I have figured that out.


I thought it best to keep things loosely in the family and pull the jets off a Bomedier (owns Learjet) 605. That means the General Electric CF-34B.

Let us do some comparisons:

OE equipped GE CJ610

  • Length: 45.4–51.1 in (1.15–1.30 m) (depending on accessory equipment installed)
  • Dry weight: 396–421 lb (180–191 kg) (depending on accessory equipment installed)


  • Maximum thrust: 2,850–3,100 lbf (12.7–13.8 kN) at sea level
  • Specific fuel consumption: 0.96 - 0.97 lb/(lbf·hr)

Now the GE CF34

  • Length: 103 in (2.6 m)
  • Diameter: 49 in (1.2 m)
  • Dry weight: 1,670 lb (760 kg)


  • Maximum thrust: 9,220 lbf (41.0 kN) at sea level
  • Specific fuel consumption: 0.69 lb/(lbf·hr)

So roughly add 2000 lbs of weight for almost 5 times the thrust

update: made a mistake calculating with the power from only one engine

With the CJ610 power to weight is .22 .443

With the CF34 it is .69 1.366

Though unless I could also raise the max take off weight from 13500 to 15500 then I lose 2k lbs of cargo capacity.


But I might be ok with that for 3 time the power to weight. Talk about unrestricted climb.

*yes I know I am crazy*

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