• Welcome aboard HomebuiltAirplanes.com, your destination for connecting with a thriving community of more than 10,000 active members, all passionate about home-built aviation. Dive into our comprehensive repository of knowledge, exchange technical insights, arrange get-togethers, and trade aircrafts/parts with like-minded enthusiasts. Unearth a wide-ranging collection of general and kit plane aviation subjects, enriched with engaging imagery, in-depth technical manuals, and rare archives.

    For a nominal fee of $99.99/year or $12.99/month, you can immerse yourself in this dynamic community and unparalleled treasure-trove of aviation knowledge.

    Embark on your journey now!

    Click Here to Become a Premium Member and Experience Homebuilt Airplanes to the Fullest!

BLOOP 4 Twin

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

SlowFlyingObject

Captain Turnbuckle
Joined
Jan 3, 2023
Messages
98
Location
Florida
Howdy,

There have been lots of posts on Redundancy lately. For the Bloop 4 I have in progress, that is a Moster 185 + Hand Deployed Parachute. For quite some time I was toying with the idea of twin electric motors for simplicity and reliability. It's not going to give me what I desire in mission range just yet. Watching Mike Sandlin's Bluebird fly, I'm strongly thinking about doing dual Atom80s. Think Lazair but as a twin pusher. One motor wouldn't be sufficient for most takeoffs but could get me back to field should I lose an engine. I may also be able to extend the TBO if I can run lower RPMs with the ever so slight increase in thrust.

I know I'd lose some efficiency spinning two props. I'd also add some weight having dual motor mounts, fuel lines, throttle linkages, frame bracing, ect. It would also give me a frame I could change over to Electric someday should I get too many noise complaints or battery tech catches up. I'm also considering this as I'm (175-185) 25-30lbs heavier than Mike Sandlin. So instead of adding weight to the tail or shifting the pilot position from the plans I could add this motor!

I can run models on weight, balance and thrust numbers... what I don't have a clear understanding on is how the turbulence from the propwash coming from each side will change performance. I ponder this as many twins have twin tails. Has anyone here placed two engines on a single engine design? The numbers seem to work out but will two motors change the wake on the rudder and elevator much? Mike Sandlin's Bloop 1 was a twin tail and may have been best suited to the twin Atom80 setup.

BLOOP 4 (without motor) - 168-178lbs
With Moster 185 - 200-210lbs - Thrust 171lbs (2 blade 130cm) 8500rpm
With Dual Atom80 - 214-224lbs - Thrust 242?, 121lbs each (2 blade 130cm) 9650rpm - ideally, with the extra thrust, I'd back down the RPM quite a bit.

On the weight, I feel I have enough wiggle room for added frame supports, motor mounts and what not to double. Vittorazi has a new Cosmos 300, that may also qualify... but it's new, not as well proven as these two motors. I'd like to keep the motors separated as opposed to linked, spinning a single center prop. She'd probably fly a little faster and stall speeds changing of course but hopefully not too much.

STEAR.png
TB001.jpg
Bloop 1.jpg
Thanks for the ever interesting points of view and words of wisdom!
 
Last edited:
Back
Top