Low-powered, four-seat homebuilts?

Discussion in 'General Experimental Aviation Questions' started by cluttonfred, Nov 20, 2019.

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  1. Nov 21, 2019 #21

    Victor Bravo

    Victor Bravo

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    The "stretched" experimental PA-22 derivatives will give you a "Poor Man's Bearhawk". Not as good of an airplane by any means, but the same category and class.
     
  2. Nov 21, 2019 #22

    tcrbaker

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    Don't leave out the Davis DA2.
     
  3. Nov 21, 2019 #23

    Pops

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    My daughter and her husband used to have a 1963 Cessna 172 with the Lyc - 360 , 180 HP conversion and the STC 200 lb GW increase. I like it better than a C-182. ( Bush Conversion).
     
  4. Nov 21, 2019 #24

    Vigilant1

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    4 seats? There were a few DA3s built, which were slightly bigger DA2s and had a small rear seat. O-200 power.
     
  5. Nov 21, 2019 #25

    Turbine Aeronautics

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    It will be making a comeback! Standby for a new improved version that a tall person can fit into and the stall won’t flick it onto its back. Maybe with a 200hp Turbine in it... :fear:
     
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  6. Nov 21, 2019 #26

    litespeed

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    For two adults, two smaller or one big adult and distance on a budget?

    Jabiru J430 cheap, efficient, range and low running costs.
    All on just 120hp.

    Limited by weight but almost everything is.

    Rare to find a true four big adult seats and full fuel machine.
     
  7. Nov 21, 2019 #27

    cheapracer

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    No.
     
  8. Nov 21, 2019 #28

    henryk

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  9. Nov 21, 2019 #29

    cheapracer

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    ? I thought they were a 2 seater, and I can't find reference to a 4 seater version?
     
  10. Nov 21, 2019 #30

    BJC

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    It takes two, similar to the P-82.


    BJC
     
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  11. Nov 21, 2019 #31

    Victor Bravo

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    As I said, I have personally seen Toobuilder's PA-22 E-AB project and it will do this mission with a fair amount of panache. Cheaply.

    For those wanting even more room, in between the "stock" PA-22 derivatives and the magnificent Bearhawk there is the Bushmaster, which is a PA-22 that is cut and stretched (like the fuselage "plug" in various different versions of the same airliner).

    The Bearhawk uses a better airfoil and some really nice aerodynamic cleanup compared to the Tri-Pacer offspring.

    But as the great race pilot Ray Cote told me many years ago... "Speed costs money, son. How fast did you say you wanted to go?"
     
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  12. Nov 21, 2019 #32

    cluttonfred

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    When I run the numbers I actually find that three, not four, seats might well be the best option for a "plus size" but simple and economical homebuilt (think "Dahu Jr."): three adults or two adults and two small kids for a day trip or two adults and generous baggage for an overnight trip.

    Messing around with one of the LAA design spreadsheets for a simple wood- or tube-and-fabric design with tricycle gear, no flaps, Hershey bar wing, 20 U.S. gallons of fuel, and 100 hp engine (Suzuki conversion/Rotax 912/Continental O-200) I get these numbers:

    PRELIMINARY PERFORMANCE ESTIMATE FOR PROPELLER DRIVEN AIRCRAFT

    Crew weight 600 lbs
    Fuel + baggage weight 120 lbs
    A/C empty weight 800 lbs
    Total weight 1520 lbs

    Stall speed (flaps up) Vs1 50 mph
    Climb airspeed 65 mph (climb speed = 1.3 x stall speed)
    Climb airspeed 95.3 ft/sec

    CLmax 1.5 (flaps up)
    CL at 1.3 Vs 0.89 (at 1.3 Vs, CL = CLmax x (1/1.3²))
    Wing area required 158.3 ft² (L=1/2 rho V² S CL)

    Propeller efficiency at take-off 70 %
    Propeller efficiency in the climb 75 %
    Propeller efficiency in the cruise 85 %
    Cd (profile) 0.01
    Cd (parasite) 0.015 (Speeds between 1.1 Vs and 2.7 Vs)
    Aspect ratio 4.95
    Induced drag factor K 1.2 (Cd (induced) = K CL²/π A)
    (K = 1.0 elliptical wing, 1.1 moderatly tapered, 1.2 rectangular)

    Wing span 28.0 feet
    Mean wing chord 5.66 feet

    ESTIMATED PERFORMANCE WITH AN ENGINE OF YOUR PROPOSED RATED POWER

    Selected rated shaft power 100.0 BHP
    Effective flat plate area 4.48 ft²
    Take off run 607 feet
    Rate of climb at 1.3 Vs 1075 feet per minute
    Max level speed 140 mph
    Cruise speed at 75% power 127 mph
    Flaps up stall speed 50 mph
    Glide descent rate at 1.3 Vs 553 feet per minute ​

    I kept the stall speed at 50 mph and the aspect ratio relatively low for an easier build (shorter wings) and to prevent float on landing since there are no flaps. Solo, the climb would be over 1600 fpm and an economical 55% throttle would still give about 115 mph cruise at full gross and 400+ standard miles range with 45 min reserve.
     
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  13. Nov 21, 2019 #33

    cheapracer

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    Yup, extra wide cabin, higher rear seat with the rear Pax legs in between the seats.
     
  14. Nov 21, 2019 #34

    Vigilant1

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    This page has a few specs on the DA-3, and a picture of one example:http://www.angelfire.com/ks2/janowski/other_aircraft/Davis/
    With a 22' wingspan, a claimed 1600 lb MTOW and 100 HP on the nose--well, I'd have to see that climbout at gross weight on a warm day.
    They also show a DA-6, which had 3 or 4 seats and an O-235 engine.

    This page appears to show a fairly comprehensive list of Davis aircraft registered in the US. N3499 is a DA-3 claiming 4 seats and was registered in Texas, so it might have been registered to Leeon Davis.

    There's also an interesting "Tecumseh Special" (N200AM) that was registered in Iowa and claimed 4 seats. Hmm.
     
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  15. Nov 22, 2019 #35

    saini flyer

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    Matthew, those specs make complete sense for 2+2 and they also look very close to LSA specs. In order to deduce the length of the cabin, I superimposed MCR4s and RV8 on RV12(keeping the rudder pedal location same).
    upload_2019-11-21_21-32-17.png
    upload_2019-11-21_21-33-57.png

    The rear cabin bulkhead is at a position that allows a nice 2+2 setupas is clear from the pics. This was very interesting as the aft baggage compartment without fuel tank can take ~225 lbs and there is enough length to seat forward facing second row occupants by modifying the rear fuselage.

    Also, the first Jabiru 2200 install in RV12 yielded an empty weight of 700lbs so using the tail cone, tail feathers, and RV12 wings as is from the kit and redoing a rivet & gusset fuselage with square tubing as is discussed in other threads on HBA might get close to 650-700 lb payload!! ​
     
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  16. Nov 24, 2019 #36

    bhcishere1

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    There were actually only two DA-3's built. I own the one built by Leeon Davis. Nice flying plane. I fly as a two seater but the plane is registered as four seats. I would not consider it a four seat with the current O-200 engine.

    The DA-3 has a good amount of space. To make it a real four seat, I would move the fuel tank from the firewall to the wings which would allow for installing an O-320. Would need to beef up the main gear for the additional weight.

    As a two seat the plane makes a nice LSA.

    The plane is available for sale. The new owner would also have the rights to the design. I would like to see someone create drawings from the plane and make it available to others.

    Bryan
     
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  17. Nov 24, 2019 #37

    Vigilant1

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    Bryan, thanks for chiming in. The only info I'd seen before on the DA-3 was at the site I linked, and there's not much there.
     
  18. Nov 24, 2019 #38

    Interstellar

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    Robin DR-400 ?
     
  19. Nov 24, 2019 #39

    cheapracer

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  20. Nov 25, 2019 #40

    BBerson

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    Avid Amphibian is three seats with low power (65hp) . Large span, folding wings.
     
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