Engines: Cost and weight per HP

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Armilite

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BJC

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Marc W

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Marc, is that the installation on your Thatcher CX4? My Sonex is setup the same way (I think most Sonexes are like this, though those who have fitted the turbo had to move the cooler to the top of the engine, as it is done on the Onex). It works well, and keeps the air duct and oil lines short. It does make changing the oil a bit of a bother since the oil cooler has to be moved to remove the cover and screen installed on the bottom of the oil pan.
Yes, it is on the CX4. You are right about changing oil. I have to remove the airbox and unbolt the cooler to get to the drain plug and screen. There are just 4 bolts holding the cooler and it hangs on the hoses so it isn't to bad.
 

Vigilant1

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A cleaned-up and revised edition of the chart. Thanks, narfi, for the chart configuration tip.
Changes:
- Added Casler/Hummel "2400" engine
- Modified the 1/2 VW engines to reflect the price of a new case (previous chart used the price for use of a reconditioned case). This is more consistent with other entries inthe chart (except the Corvair). A new case adds $700 to the price of the 1/2VW

Observations:
- A hand-propped 1/2 VW (37 HP) costs the same as a hand-propped 4 cyl 1835cc VW (60 HP). As Pops has said, the hand-propped 1835cc VW gives a lot of bang-for-the-buck. But, if you need a 37HP to 45HP 4-stroke engine of less than 100 pounds, whatchagunnado?
- In the bang-for-the-buck category, the math indicates Hummell/Casler 2400 engine to be a pretty good bargain, especially as it includes dual ignition, electrical system, starter, etc.



Engine
HPCost($)Weight
(lbs)
$ per
HP
Lb per
HP
Notes
Lycoming O-360
18027,500
305
153
1.69
1
Continental O-200A
100
23,500
205
235
2.05

Rotax 912 ULS/S10019,4371251941.25
Aeromomentum AM1310010,495201105
2.012,3
Corvair 100HP
100
10,500
219
105
2.19
4
VW 2331cc Revmaster
85 (80)
9,400
170
111
2.00
5
VW 2387ccHummel "2400"
85 (?)
7,275
170
86
2.00
6
VW 2180cc
76
7,175
167
94
2.20
6
VW 1835cc606,025165100
2.757
VW 1835cc 'basic'604,750145802.428
1/2 VW (1037cc)
37
5,775
100
156
2.70
6
1/2 VW (1037cc) "basic"
37
4,750
85
99
2.00
8
Briggs&Stratton 810cc
30
830
87
28
2.90
9
" " + hub&bearing
30
980
94
33
3.13
10
Harbor Freight 670cc
22
730
97
33
4.41
9
" ^6 + hub&bearing
22
880
104
40
4.73
10

Notes
(1) Price through Van's direct purchase program. May be higher elsewhere?
(2) Price is for the Aeromomentum AM13 "low profile" version. The upright version is $8495
(3) Weight is for the AM13 engine, radiator, and coolant
(4) Azalea Aviation "Spyder." 120 HP also available, ($12,900)
(5) Revmaster "R2300." 85HP max, 80HP continuous. 94mm bore, 84mm stroke
(6)
From Hummel engine site, includes dual ignition system, starter, alternator, carb, Force One bearing and prop hub
(7) As above, but simple shrink fit prop hub (no Force One bearing and hub)
(8) Hummel engine site: Single ignition, hand propped, no alternator, with carb
(9) Twin. Includes factory flywheel (incorporates factory stator/generator and ignition trigger, etc)
(10) Estimated future price and weight of additional bearing and prop hub: $150, 7 lbs.[/QUOTE]
 

Vigilant1

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- Are there other industrial engines we should add?
-- That B&S 540cc vertical single (of 19 or 21 HP)? Is removing the 6 lb balancer and turning it horizontal really practical, or will it shake itself/an airplane to atoms? $559/19HP = 29.42, slightly higher than the B&S 810cc twin.
- Any 4-stroke cart engines/small vehicle engines available as crate engines?
 

BBerson

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- Are there other industrial engines we should add?
-- That B&S 540cc vertical single (of 19 or 21 HP)? Is removing the 6 lb balancer and turning it horizontal really practical, or will it shake itself/an airplane to atoms? $559/19HP = 29.42, slightly higher than the B&S 810cc twin.
- Any 4-stroke cart engines/small vehicle engines available as crate engines?
Without the balance it might be same as older single cylinder Briggs. It is just the cheapest. Two could be connected for 1080cc. at around $1000. Probably easier to get the Robin/Generac ($2000) if they still make them. Those could be the remaining stock on hand. I heard they were discontinued. But changes hands frequently.
 

pictsidhe

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It would be possible to belt or chain drive an external balancer to just about any engine. This would be the easiest way to make an excessively vibey unbalanced engine usable.
 

Lucrum

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table.jpg

Just for comparison and using published numbers for the unmodified version of my engine. (Mine is modified)

Engine

GE T-58-8B

HP

1325 for 5 mins

Cost

$26,000 or so

Weight

270 lbs

$ per HP

$19.62

LB per HP

0.2038
 

pictsidhe

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That's a hard post to follow.

Back to the teensy weensy stuff, though.

The 77lb Briggs vanguard 627cc 23hp engine has a 19lb flywheel. The starter is about 6lb. Yep, just over 50lb without those two bits. You'll need to sort out a new ignition and prop hub, but that should be <60lb direct drive. It could probably be tweaked up to 25hp. I suspect that larger twins may see a similar weight drop. I'd love to know what the 993cc flywheel weighs...
 

Norman

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Polini Thor 250, 36.5 hp, weighs about 44 pounds without the radiator. It looks like a nice little engine: dual sparks, dual independent ignition, internal balance shaft. The factory radiator mount is a bit wonky but it's designed for powered parachutes where the frontal area wouldn't be much worse than the pilot alone.

Polini-Thor-250_factory-setup.jpg
 

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pictsidhe

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Polini Thor 250, 36.5 hp, weighs about 44 pounds without the radiator. It looks like a nice little engine: dual sparks, dual independent ignition, internal balance shaft. The factory radiator mount is a bit wonky but it's designed for powered parachutes where the frontal area wouldn't be much worse than the pilot alone.

View attachment 73622
Yours for just under $5k
 
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