HP Gold Cup 40 R/C Rear Intake Engine #99-2104
HP .40R GOLD CUP .40 Gold Cup
Rear Intake Radio Control #99-2104

This is the only .40 rear intake engine that boasts the high performance of a rear rotary valve design with reliable throttling ability. Radical intake and port timing produce fantastic top end with idling reliability only slightly compromised.

This is the only .40 rear intake engine available today.

Also Available in Free Flight/Control Line versions.


.40 cu.in. (6.44ccm)
Bore x Stroke
0.827" x 0.732" (21mm x 18.6mm)
1.26 hp @ 17,000 RPM
RPM Range**
3500 ~ 20,000
Weight (engine)
10.4 oz (295gr)
Prop Size
9x8 -- 10x5 -- 10x6 -- 11x5
Prop Nut Thread
Piston/Cyl Type
Conventional Ringed ABC
Hardened supported by two ball bearings
Intake Type
Rear Rotor Disk Valve
Connecting Rod
Forged Aluminum Bushed at both ends
Carburetor Type
Twin Needle
Schnuerle with boost ports
Glow Plug
K&B 1L 7311 Std Long
*Power rating is absolute maximum using high nitro fuel and tuned pipe, your result may vary.
**RPM range is the range the engine is capable of, your results may vary.


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