500 mph Fenix II ?

ZDZ420 powered version added above.


An idea came up and totally doable.

Take two of these 420 ccm ZDZ 35 hp engines; http://www.troybuiltmodels.com/items/ZDZ420B4.html

Install them in FNX II and tweak them to 60 hp to run at 8500 rpm. Then put two 25x38props.

I calculated the props will stay at 607 mph ( 970 km/h ) and the plane could be really fast at low cost.

Topspeed would be at 510-560 mph depending how clean the airframe will become ( retracts are doable ).

Standard engines at 25/36 prop could yield 280 + mph speeds.


  1. How about a cheap jet fighter version?

  2. Antaisitkos vähän laskutoimitusta tuosta 560 mph ja 60 hevosvoimaa (vai tarkoititko 2x60hp)? Eikös se ilmanvastus kasvanut jotensakkin neliöön nopeuden tuplaantuessa? Plus että tuota "märkäpintaa" on kuitenkin jonkisen verran. Ei kuulosta näin äkkiseltään uskottavalta. Mutta empä minä näitä ole laskeskellut, siitä mielenkiinto.

  3. No one prohibits if converting this to a jet version.

    My speed estimates are for 25/38 propfans at 8500 rpm.

    I would have at 2 x 60 hp better power to weight ratio than a stock P-51D.

    So I assume a gas engine of 7500 rpm could be switched to use methanol/nitrous fuel and produce 20% more power ?

    I did calculate the prop tip speed would stay under 970 km/h so clearly under the speed of sound.