GeeBee Sportster - swappable.

by alibopo | November 18, 2013 | (11) Posted in Projects

GeeBee Sportster - swappable.

 Built as a test fuselage in my 'Tribewt' build article - this plane finally got its wings, a paint job and a maiden.

There was a slight power issue at the start of each flight, with the prop only achieving full revs once the plane had picked up speed - which suggests to me the prop I was using had too much pitch. I'll reduce that for the next outing and see what happens. I'd rather sacrifice a little top speed in exchange for power-now! Though it may be that the motor will perform better in all areas with the reduced-pitch prop. Other than that it was a very satisfying series of flights. I'd like to be able to throw it about the sky a bit more, but I need a bit more time on the 'sticks' before I get that confident.

Another issue was excessive 'spring' in the landing gear - I tried a ground take-off, but the plane just leapt about like a kangaroo until it did a nose over.

To combat this I've stiffened the landing gear by cross-linking the top of the struts with an extra piece of piano wire bound on with thread and CA glue - hopefully that will make a difference. 

In terms of scale it is what it is. I've tried for the 'look' of the plane and overall it's pretty close. Wingspan is a little less, and the tail surfaces a little larger.  

Here it is ready for paint.

The 'blue' is sticky-back plastic. The front is polystyrene painted with 'pewter' acrylic. 

Here's some extra cosmetic bits added after the maiden; a little headrest, some padding around the cockpit and a windscreen. 

UPDATE - here's a link to plans for the plane; GeeBee Sportster Tribewt

COMMENTS

RICHGCOOP on November 20, 2013
It keeps getting better and better. Keep up the good work.
RICHGCOOP
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alibopo on November 21, 2013
Thanks for that, cheers.
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nickhart on November 21, 2013
Nicely done!
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alibopo on November 21, 2013
Thanks!
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LordVader on November 20, 2013
Really nice job. Would love to give this a try. Thanks for sharing.

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alibopo on November 21, 2013
Thanks for the comment!
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rcmaster17 on February 1, 2014
you need to make plans
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hellcat on February 8, 2015
hi have just dry fit the geebee together made from 3mm coreflute dry fit with servos. no battery and motor yet 380 grams ive increased the wingspan to 900mm. motor and battery esc and rx undercarriage will take it to 800grams or there abouts. the motor is a monster. this coreflute really looks a good option cheap and very strong. doesn't mark like foamboard surface can be painted with turps based spraycans or or covered with colored tape or sinage film glues up well with hot glue uhu or selleys durabond gorilla glue and very small amounts needed if you want any piccies or movie for maiden when it happens here is my email barberr@squirrel.com.au
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hellcat on January 29, 2015
Hi really nice job I have started building one so thank you for the plans.
I usually use depron but have got interested in correx sheeting 2mm. i get it for 4$ a 6x3 sheet
the wing has formed up beautifully and is super strong and the weight is well within what I would expect.
just as a matter of interest what is the flying weight of your build???
Thanks again Ross from OZ

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alibopo on January 29, 2015
Hi - that's good news. Glad to hear the plans are working out for folks. My build turned out at 820 grams / 29 ozs with a 1000mah battery (6 mins of flight). If you built it with the wider 840mm wing it's going to carry more battery with ease and get better flight times. My planes always turn out heavy due to the foam board I'm using, but they stay a little more stable in wind. If you've managed under that weight (which is very likely) it'll fly reasonably slowly. If you are flying slower - switch from bank & yank to more rudder-type turns and keep the wings flatter (you need something to keep you in the air at those speeds!).
Cheers.
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hellcat on January 30, 2015
thankyou for the info and advice. am finding ways to work the correx/ corflute all going well.
body is under way. By the way i have built 2 wings. one is as per plan with dihedral. the other is flat no dihedral but ive increased the size of the under camber sections by 30mm each side. will see what differences there are. what i like about the correx is i can slide thin carbon fibre strips( i get from a friend waste bin who makes arrows )into the correx flutes where needed to stiffen and to join the wing tails elevs rudders ailerons sections positively and is a very neat
kind regards oh and am already scheming to have a go at emulatind your very nice avro
Ross
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alibopo on January 30, 2015
I'd love to see some flight footage once you get it in the air. Did you notice I've also got plans for another biplane, the Polikarpov Po-2. Nothing wrong with the AVRO, but the Po-2 is a sweet plane to fly with great presence in the air. I've also got plans for an SE5a, which I'll release once I've built it myself - should be finished in another two or three weeks time.
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hellcat on January 31, 2015
will do re flight footage and will look at the po-2
just aquestion I am having trouble getting emax motors in oz do you have any suggestions for an equivalent turnigy which are easy to get here? i have a Turnigy D3542/4 1450KV Brushless Outrunner have used it in my scaled up baby blender (900mm wing span) Messerschmitt and a stearman goes like the clappers but draws heaps on a 3 cell
thanks again
Ross
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alibopo on February 1, 2015
Hi Ross, sorry, I doubt I can help with the motors, though a trawl through HobbyKing's pages should throw up some interesting comparisons even if you didn't go to them for the purchase. I'm not absolutely sure. but I think they have a 'store' in Australia. http://hobbyking.com.au - if that's no good, how about approaching some of the other OZ contributors - apnewton springs to mind. He seems pretty knowledgeable and approachable.
Cheers.
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hellcat on March 6, 2015
I certainly have had fun with this build Lola wasn't built for comfort, like her 30s predecessors she was really really built for speed. the change to build correx was really worth it
Thanks again
Ross
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hellcat on March 4, 2015
Hi, just letting you know the plane now called Lola flew on the maiden beyond expectations incredibly fast rolls loops and climbs vertical with ease. I used the 900mm flat wing which I cant fault. It was very soggy on the field and grass was unmown so lets just say as you have experienced she is a handful on landing in the long grass I will install flaps. the landings looked hard but the correx is very tough so no damage at all just few paint scratches on the wing leading edge. The day was cloudy with rain coming across periodically in squalls our wet season post cyclone Marcia. My video man was not around but next Monday with a mown strip at the field will be the go.
Ive started an article Correx prototype Gee Bee Sportster (Pending Approval)
I have acknowledged your work on this model in it
kind regards
Ross
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alibopo on March 5, 2015
Hi Ross, sounds like you're having fun - looking forward to seeing some flight video. Cheers :)
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hellcat on March 21, 2015
Finally got I article on Lola posted hope you like it http://www.flitetest.com/articles/correx-prototype-gee-bee-sportster
Kind regards
Ross
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hellcat on February 1, 2015
thankyou for the suggestions will let you knowhow it all goes
kind regards
Ross
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Drbudd on September 14, 2017
I just finished a gee bee going off the baby blender design and yours. Ill post a pic later.
I managed to get a fully round front half of the fuselage
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alibopo on September 14, 2017
I'll look forward to seeing that. Did you increase the wingspan? My 'original' had slightly 'stubbier' wings, and on my plans I suggested increasing the wingspan to bring the flying speed down. Did you also look at 'Hellcat's 'Lola' just above - a very sweet flyer, but no dihedral which made it slightly less 'beginner' friendly - no problem for an experienced flyer, but I like that little bit of self-righting effect. Cheers, Alistair
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GeeBee Sportster - swappable.