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Old May 05, 2007, 06:10 AM
Tony65x55 is offline
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I'm not flying backwards!
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Oshawa, Canada
Joined Sep 2004
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Build Log
** Blu-Baby Primary Trainer ** Plans, Pics and Fun!

The Blu-Baby. Is this the World’s Greatest Primary Trainer?

Well no, probably not. But after numerous requests from RCG’ers (and apologies to those who patiently waited for it), let me introduce you to the Blu-Baby, one of the sweetest little aircraft I have had the pleasure of flying.

It was developed for a specific reason; to provide a platform that my flying buddy, Airplane Ed, and I could actually fly inside an armoury without bringing home a bag of parts after every flying session. You see, we’re not very good pilots and concrete walls, terrazzo floors and steel beam ceilings are murder on our dumb thumbs. Every indoor session was followed by three nights of rebuilding and that was getting pretty thin. As we have a pretty long indoor season up here in Kanuckistan (nine months of winter, three months of road repairs) something clearly had to be done.

Enter the Blu-Baby. She is a 3-channel high wing monoplane of 33.5” span. She sports oversize tail surfaces for exceptional stability, moderate dihedral for tight turning and spiffy looks, a 4-40 undercambered airfoil wing with generous area for slow speed performance and pleasant stall characteristics and a simple taildragger gear with a rear landing skid. The Blu-Baby pioneered a method of construction I refer to as ”monobloc” construction, a technique I now use on many of my planes.

The monobloc method consists of sandwiching a solid pink foam block between layers of fan fold foam. The motor mount, battery bay and landing gear mount are all integral to the monobloc. The motor mount and LG are glued in place with PU glue and although I have had to redo the motor mount occasionally after impact with a concrete wall, I have never had a LG rip out. On large aircraft the monobloc can be reinforced with a couple of bamboo skewers PU’d into grooves cut into the sides of the monobloc.

As the fuselage sides glue directly to the perfectly flat monobloc sides, this construction method ensures the fuse is built perfectly straight and true. It also renders the forward fuselage “Brute Tough”, able to withstand abuse that would destroy a normal foamy. Best of all, this is done with little weight penalty as there is certainly not much glue (and no epoxy) present in the front end of the plane.

The Blu-Baby has been built in three different sizes, a 33” indoor and park flyer, a 42” park model with a GWS 350 for the Kid and a 60” AP plane with an accessory sport wing with no dihedral and full span flaperons. All three sizes have exhibited the same kind flying characteristics, super docile handling, very gentle stall and all around great manners.

The Blu-Baby can fly on several different power plants with great success. The first two 30” models used a GWS LPS and worked great. While they flew well, we dropped the LPS from the “recommended” list because of its fragility. One plane received a GWS IPS and the other got a J250 in a GWS “C” drive. The IPS is terrific for putting around indoors and the J250 is overpowered but fun. The 42” has flown on the J250 drive too but currently wears a GWS 350. The big AP bird flew nicely on an inexpensive BP21 and it now carries a ST Models 1000kv brushless for hauling around cameras.

This is a very easy airplane to fly. How easy you ask? Well, I’m glad you did. After two years of flying around indoors, dumb thumbs and all, both of the original planes are still in service and flying great. The Kid’s 42” is still in flying condition after innumerable contacts with the ground and two unplanned landings into the back of Airplane Ed’s pick-me-up truck. My AP bird still continues to click away over the skies of Oshawa.

Best of all, I have taught three different people to fly RC using the little Blu-Baby with the IPS in the nose. Time to solo: 15 Minutes. That’s right. Three different people who could successfully navigate the Blu-Baby across the skies in only 15 minutes of flight time! Easy to fly is an understatement.

* NOTE: Since the beginning of this thread, literally hundreds (maybe much more) of people have successfully built and flown this aircraft. For many, it was their first successful RC airplane. These pages are full of testimony to the simple build and easy handling characteristics of the Blu-Baby. Almost anyone can build and fly this aircraft.

Veteran RC pilots will likely be bored to tears with the Blu-Baby but it isn’t made for them. It is made for someone learning to fly, someone who want a nice docile indoor or cul-de sac flyer or someone who just wants to kick back and not have to think about it. It makes a Slow Stick or a GWS Moth look positively twitchy.

It is super strong to withstand those less than perfect beginner landings, built easily with a very low parts count (13 including control surfaces) and uses super cheap off the shelf components.

A friend of mine wants to learn how to fly RC and I will be doing this build for him. So far, he has completely destroyed a Slow Stick and an E-Starter but I think he will be able to fly this one. The plans below are presented with two different vertical stabilizers, a modern looking one and an old timey looking one. Both work well, so build whatever one spins your dials. As well, the wing mount has cut lines on it for both a 4-40 undercambered airfoil and a top step KFm. While the KFm has not been tried on this plane it should be fine for those that are looking for something a little different. The wing plan also outlines the piece necessary for the KFm top step. When rolling the camber into the 4-40 airfoil, the curvature should be rolled in parallel to the LE of the wing. This will automatically put the correct amount of washout into the wing tip.

I have not flown any airplane that was easier to fly. You can see the Blu-Baby flying indoors at:

Try one and see if you agree.


PS: Plans for the 42" Park Model and the 52" Aerial Photography model are on Pg.8, post 107.

For a simple video lesson on how to roll a Blu-Baby 4-40 undercambered wing, click here:
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Last edited by Tony65x55; Sep 28, 2008 at 08:30 AM.
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