OzMo

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the ozark mountain barnstormers (ozarkmtnbarnstormers.com) did a winter scratch build of Dave Robelen's PARAKEET, a biplane version of his popular Pronto. i am sad to hear that mr. robelen passed away this april 7th, we will miss him.
we partially built the kit as a group to ensure accurate decallages. each fuse and pylon was placed over the plan before gluing. so each plane should have accurate wing mounting angles and tail feather bases. motor mounts are pre cut and the details for side and down thrust are shown in the pics.

we first made a parts list then began" kitting" the plane and piling up parts. we started with the balsa fuse and tail feathers and wing tips. this line of planes is based on the lesser cost 3" x 36" balsa sheets 1/8 and 3/16 were common with some 3/8 for rhe pylon for the top wing. we opted to do foam wings and a built up version of the pylon base. we also did away with the stringers for the turtle deck and made it from foam.

the foam turtle deck is glued to the top(hard to see in pic) of the fuse it has some 1/8 square stringers glued to the fuse for suport.

OzMo

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here are some details from the plans and some wing angle details. the motor mount called for maple but we hab some nice oak do we will just be a little careful to predrill our mounting holes.
the topwing sweep is shown here we will use the excess foam from the top wing to build the center section, the plans show a solid balsa block, we will fiberglass the joint to get strength. the built up version had ply spars. we did use dowel LEs as per the plan for ease of shaping and strength.
also note the detail for the wing struts, we made no changes here as the concept was a real winner and typical of a Robelen design.
it uses four 1/16 ball link sets with the cup portion bolted to the strut top and bottem and the ball glued into the wing we will use a 90 degree bent rod and set it with epoxy into the foam wing, a small peice of dowel could be used as well if desired. i will post pics when i build this portion.
hold off on cutting the wing tapers until i post some better pics. we found good old white glue or carpenters glue was great for sheeting the wings. we also discoverd clamping more than 2 wings together to dry produced some nasty warps...warps don't come out of sheeted wings so we used 'em to do break strength tests and wow are they strong!
the top wing center section is 3" wide with dowel LE and TE stock for the TE shetted with 1/16 ply there is no taper or dihedral angle to this part dihedral angle wil be sanded out of the wings aftersheeting and sweep back angles are cut. NOTE this was originally a high dihedral design as it was rudder and elevator without ailerons less dihedral may be a builders option if ailerons are chosen.

OzMo

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more parakeet stuff
youl notice that the pylon for the top wing ( plan detail in the first post) is made with a plywood base and has some ply tapered strips to hold the 3/8 pylon with some 1/8 or scrap balsa on the sides to hold the 1/32 or 1/64 ply exterior this was to replace the balsa block and served well as a lesson in that type of construction but i think the balsa was a better way to go for simplisity. this block or assembly is hollowed out some in the forward area to allow the fuel tank to sit up(needed for good fuel draw). the plans call for a 4 ounce tank but i opted for a 6 ounce tank that requires some slight mods to the former behind the tank. either way cut out enough to allow some foam on all sides of the tank i cut apprx 1/8 inch extra all around by tracing my tank outline onto the ply pylon bace the used a dremel to cut away the excess. TAKE YOUR TIME WITH THIS! more to come
note: the second pic is a detail of the pylon structure shown is an attempt to sheet it with 1/16 balsa WELL it didn''t work worth a poopso we went to 1/32 ply not cheap but works slick!

build light

I don't know why no one else has replied so far... I really like this plane and want to see more!

I have been watching from day one. Great pics and detail!

Robert

BMatthews

I think everyone must be out flying thanks to the improving weather. But this is a great idea for a thread. Keep 'em coming OzMo ! ! !

BantamTJ

Hey OzMo,
Great documentation on the build thread. I keep checking from time to time. Need to p/u my plane so that I can "follow along" as this thread progresses.
Good job with the pic's too!
Talk to ya later when I return home from workin' in the arctic [&:]

OzMo

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hi to all following this post.
have been busy training new students and getting over a little disk fusion but the guys in the club are hounding me to get after this soooo...... after Labor Day weekend I'll try to do a little on this each week with posts. the Sept MODEL AVIATION shows another clubs group picture with 6 of the Parakeets on page 154...Dave Robelen designed some sweet planes.

parakeet plans ...AMA #541C

joshman123

i would like a set of wing cores. i have several D.R plans. but not the parakeet, although i have a fuse that was built loong ago. dave was in our club in the 80's.

OzMo

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Joshman sent you a pm
not in the wing core makin biz right now to much time at work these days with kids in college and all that stuff.
this build post should resume soon as the flying season pretty much goes downaround here when daylight savings time ends. So check in here now and then.

rainedave

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Just bumping this one up. I hope to see more progress soon. This is a great project; I've wanted to build a Parakeet for about 15 years.

David

AlphaWhisky

I`m intrigued with all this. Can someone post a picture of the finished article.

Are plans available, and where may they be obtained....?

Alan W

OzMo

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Well we haven't finished any yet. I am not sure its legal to print off plan copies. We should be
restarting this project very soon though and I might make a batch of copies if its legal. If so I will make them available at cost. Dave robelen passed away recently and I don't want to do anything disrespectful. But I think he would be happy to see his planes being flown so I will look into it.

OzMo

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Hey All
Well, after life intervened with some and family unavoidable stuff, I am digging out the Parakeets to finish this build along.
AMA has plans and a build article from the Feb. 87 MA. Plan # 541C.

Yuu

Nice to see this build getting back. Looks like a nice build for my O S .25. Keep them coming.

Oldguy1999

I know this is an old thread, but if anyone is still reading this and KNOWS where the COG is on this great little bipe, I would sure appreciate an email or PM on it.

Thanking anyone that can help me so much.. I have just purchased one of these bipes, from an estate, that has been sitting for a long time, and I have no idea where to start for a COG..

Thanks again

Denny (The Oldguy)

Dsegal

You can see the balance point in the orginal construction article in the AMA digital archive. See issue Sept., 1987. Photos of finished Parakeets are in the Februrary, 2007 issue (not in the archive.)

OzMo

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C of G is right on the fuse in front of the BOTTOM wing. it is right where the wing saddle starts, or right on the LE of the bottom wing.
it does not specify a range but a 1/4" in front of the lower LE to the LE should be ok.
I have never finished one of these, I have 5 of them with plans on the bench in the shop about 1/2 way done.[&:]
hopefully this winter I can finish them.

rocknative

Hi OzMo - Love watching these posts - learning some new things, thank you! I'm late to this thread and I hate to ask a possibly dumb question - but is Mr Robelen's Parakeet similar to, or meant to be the same design as the famous Rose Parrakeet? I have loved those little biplanes for years now! (talking about the full-scale parrakeet)...Thank you, Tim

OzMo

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HHMMMM interesting thought. Could be but don't know. [sm=72_72.gif]

OzMo

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Started to finish the Parakeets tonight. I had several "kits" from our scratch build. I am getting them all to the point where this thread left off. Then I will start adding more pictures.
Some more info came up on this plane over the lag time. I spoke with a builder that had an oportunity to speak with Dave Robelin about the Parakeet. The struts were an afterthought do to the top wings propensity to rotate. They are not really needed for strength. Several other builders have omitted them. The rotaton problem only happens with rough landings.
One solution is to have four rubber band pegs on the top wing instead of two. Super easy to do.

OzMo

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Last nights work. Attaching the turtle deck. We wanted to teach one handed hot wire cutting from a pivot point using one template (the larger end) so we have a foam turtle deck. A brace across the top and bottom help hold shape when attaching the turtle deck and the 1/16th balsa bottom.

OzMo

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we opted to build up the deck for the pylon bases and sheeted most with very thin plywood. But I had 3 that needed sheeting and ran out of ply. So I broke out some West Systems epoxy I had and some dollar store knee high stockings (six pair for a buck) stuck one of the finished bases in a baggy and pulled two of the stockings over it added a piece of fiberglass and pulled a third stocking over it. I applied about 30 cc of mixed epoxy stuck the whole thing into another baggy and wrapped the mess with a well stretched ace wrap. Came out very nice tonight. I will pop a couple o pics before assembling that one. there is a pic of one of the ply covered jobs in the first post.

OzMo

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Here are the pics of the pylon deck assembly. As this build was also a methods and mediums teaching gig we have multiple approaches to some of the assemblies.
pic one is of the bottom side of the unit being unwraped (no epoxy).
pic two shows the soft partial cured unit not tacky but very easy to trim.
pic three shows the timming. I am opting to cut the slot for the pylon later to make epoxying it to the assembly easier.
I mixed the same West Systems epoxy with some cabosil the thicken it up to glue the molded part to the assembly. In pic one in the upper left corner is an end veiw of one of the assemblies.

OzMo

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Here is a pic of the same assembly covered with very thin ply. Any number of methods will work.
shaped balsa blocks, shaped foam with fiberglass or thin balsa covering or just sheet it with flat sheets for a geometric noncurved shape. ITS ALL FUN

OzMo

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Hi bird watchers,
Well work on this project has been spotty at best. Made a couple of different versions of the top wing pylon deck. I went to the stock version, a solid balsa block after I made a potato chip out of one of the fiberglass versions. So here it is. I used the drill press with the depth gauge to hollow out the area for the tank. I used AA or better soft balsa for this piece.
#1 the potato chip...trashed[:@]
#2 deck with pylon, not glued, shown over plan.
#3 I used drill press as a mill to hollow out area that sits over tank.
#4 deck is thinner, top to bottom, at the firewall than it is at the cockpit.
#5 takes very little time to do this deck with a sharp razor plane.