Having started building this lil bute I thought I would share some of the triumphs and heartaches of the build. There are a couple of threads on this plane, undoubtedly known by many to have been first designed and build by the famous Phil Kraft of Kraft Radio Control fame, but I cannot find on any forums notes on its building.
I have the basic wing complete and am just starting the fuselage.
Note on the wing build: The wing ribs were actually individualy cut but then to make sure the spars were in the same location I placed them altogether and cut the slots. This allowed me to sand them all to an equal shape.
The LE was meant to have been 1/2 X 1/4 but Inever had any so I cut it from hard 1/4 sheet, but not very well. It ended up about 1/8 too narrow so I will fit the leading edge sheeting over the top. I prefer it that way so nothing lost there.
The U/C mounts had to be cut out for the leg to fit in. You could once get these ready made with the slot but alas not so now. I could get the bigger type that will fit the slik Fly (On my list of building projects and ordering parts for same as I write this) The cutting of the rebate for the 10g leg went much better than I expected though so I am happy with that.
I have about five 4oz fuel tanks on order and hopefully one will fit
</p>

Subscribed! Thanks for posting the build. What engine are you planning on using?

You guys are forcing me to get back on mine!!!

FB

Most modern engines seem to be ballraced and longer to boot. This precluded my first choice of an ASP21. Lots of power and light but it was about 15mm too long. The great Phil had stated that it may even need weight in the tail even with his selected engine, which never needed a silencer in those days either. I got hold of an Enya 19 TV which is just the right length and according to the reports I read should provide all the urge needed.
I wasn't sure if anyone would be interested in a build of this plane but it seems not to be the case. Currently I have started building the fuselage and await the delivery of some 3/8" triangle wood strip for the top of the Fuz. It seems to be built very strongly and I read someone saying they were overbuilt in those days as balsa was cheap. Personaly, I feel they were built just right. The ARF brigade ae buying planes that essentialy if the manuafacturers could supply air rather than any thing like real balsa are likely to do so in the name of profit. Even the kit price when these were in their heyday was quite high, but you get what you pay for and with ARF's you get nothing back in terms of satisfaction and the knowlege that the firewall (for instance) is not going to fall out because they never used enough hot glue. Sorry, don't like to rant on about the merrits of builiding your own but there is a whole generation it seems that have, or are losing the art of building.

Have you picked out your servos? One in the wing as the plan shows or one for each aileron? Are you going to use barn door style as in planes or go to strip style? If I ever get the primus finished this one may be next. Does anyone have a thought as to how much weight will be saved using modern electronics over the Kraft stuff shown? Today's 2.4 rx and two servos may weigh about what my old orbit servo weighed. Now let’s see a 1600 ma NIMH battery at less than half what a NiCad pack weighs. Could it be flown with an OS LA 15? Come to think of it there is a Kraft receiver and a couple of servos in a mason jar out in the barn with the lid screwed on tight to protect them from who knows what while I spent 30 years doing other things. Gotta buy some scales.

If you are going to do barn door style ailerons please take lots of pictures and let us know your technique for cutting out the ailerons.

I guess it would fly, by all accounts I have read) very well on a 15. Only trouble is getting the thing in a short enough version. I am going with the original single servo in the wing centre. Quick and cheap plus I get longer flight times from the battery although that really is not an issue with a 1200maH battery or more. The barn door ailerons (inset) are really superb and I will stick with them too.

Just got the fuel tank delivered. Seems like the SLEC 4oz tank should be perfect.
http://www.slecuk.com/catalogue/Fuel...cessories.html (Its the blue one at the top)

I am now progressing with that fuselage. I managed a boo boo there. I cut the fus sides too short at the front. Rather than replace them I just spliced a further bit on the front.
The fuel tank bay seems a very busy area. It has to house the nosewheel tiller, the battery (Using a flat one) as well as the fuel tank. . . Anyone got a shoe horn

Progress has been reasonable with only minor problems. Decisions mainly ! should I use two seperate servos - decided against. Nosewheel steering. Should the tiller arm be be underneath in the wind or in the confines of the tanks space and should it be a commercial item? Well, in order to fit inside you simply have to make the little blighter. I did source a suitable nose leg with coil though. The tank hatch has been shaped but needs facing with ply at either end. Great idea tank hatches as you can see when its full (doesn't take alot of time if using an electric pump to fill which usually would result it going down the pressure pipe line and into the silencer. Well thought out are Phil Kraft's designs.

A glance of the future. Now standing on her own feet, as it were. A great design.

Awesome Nigel! Keep going, want to see her done!

FB

Had a long hard think about this aileron connection. I wanted, idealy, to be able to adjust either end so I could pull both ends in to increase differential or do the opposite. Plan A/ I made up two links but found that room precluded the otehrwise good idea. Plan B/ I next went the route of the plan. Simple and effective. It has just a 90 degree wire piece soldered on which just literaly sits in the servo. If the servo was to move then it could come out. Plan C/ was an adaptation of plan B which involved having the same simple wire piece soldered on but also had another 90 degree bend so it cannot escape from the servo arm. This simple answer has two draw backs that I have to live with. 1/ If I want to remove the arm I have to remove the servo and I cannot shorten or lengthen either individualy or together the lengths. The connection to the aileron 90 degree horn at the outer end will have an extender and a nylon clevise to allow adjustment. There will be incorporated a little differential for peace of mind as well.

Any idea what the model will weigh?

What it will weigh? Good Question. From all acounts it should come in at 2.5 to 3lb, at least that is what the original was but that was with a larger heavier radio. As things are becoming completed I should get some idea.

Your thread has got me all excited again.....

I started building one early this year, but got side tracked .....

Mine is also going to be powered by a Enya 19 TV ....I found one AS New Boxed and only $60.00 AU

I am about half way complete, I am sheeting the wings at the moment once the wing is complete I will post a Pic or two......I hate sheeting wings [>:]

Good luck with the Build

Johnkpap

I have been constructing a Fly-Baby (51" wingspan) designed by Gordon whitehead simultaeneously so that is slowing me down a little. I wanted to have the wings doen on both then the fuselages etc. It didn't work out that way though. I have the fly-baby tail surfaces done (a little more to build than on the flea-fly) and am now getting the basic wing started. I have some parts cut out for the Fly-Baby's fus as well.
The Flea-fly is progressing well and I am lookin ar about 2 weeks to finish it. I have some nice Light Orange Solarfilm (Phil Krafts favourite color apparently). I am now try to finish the wings. The Tips have been added and I just have to sort out the ailerons. I have build in a little differential.
The picture shows it before the latest work on the wings was done. I also have the snakes now so they can be fitted. Not much room in that there fuel tank bay !

cute!

There is not alot of room for a fuel tank


I am going to fit a KAVAN 4 OZ or a Sullivan SS-4 both fit and I have both in my parts box.

Towerhobbies stocks the Sulivan RST-4 on the plan.

The Wing sheeting is nearly done on mine ........At last

Hmm Wing servo next .....That looks to be a right pain [] to get right

Johnkpap

Nope. Not that easy. I'd miss

I now believe I have every type that is made - the best one seems to be the SLEC but that nose wheel conection - ugh.
I may fit brakes - just for fun

Here is a picture of my wing servo installion. It may help. Done virtually as original except for the bend and smaller servo.
The bellcrank had a few degrees of differential added.

nt,

The art of building (you did write it), scratch.
I did read your post see quoted and did have to think about my Orion.
As in the past I always use one servo for the ailerons and the frise ailerons of the Orions don't need differential.
I think this can be interesting for you. Next plane or time?

I also do use one rod between the two bellcranks it is much better to prevent play, but to remove the servo I have a small detail to show.
First I can adjust the total length,second I can remove the servo much easy. (Picture 1)
Important because there is not much room in the compartment in the wing. (See blue oval picture 2)

As you did show it is very important to make fail safe solder connections.
The construction is safe, even after I did hit an object I still could control the remaining aileron.

Good luck with building and flying

Cees

I did think of going the two aileron route. This has drawbacks. Twice the servo current which gives shorter flight sessions and increases the roll inertia so I stayed with what I found to be the most solid dependable method I could adopt and that was not far from the original. I did add some clevises for assembly adjustment at the bellcrank end and I did add a 90degree kink to the servo for security. It turns out I can get the hole to be altered quite easily if I want to adjust the throw at the servo end although I think it will not be needed. There is only one rod from end to end to eliminate any slop which is the last think I want. There is a geared down drive to the servo by the use of different lengths of the bellcrank.
I am not sure what the amount of throw should be but I am certain that no differential was used on the original. Mine had just enough so that if there was any chance of the lower aileron being more than the upper one this should eliminate it.
I have today been trying to fit the steering linkage. Good fun (it isnt). However I am getting there slowly. A smaller battery pack may help. I ordered one today (800maH) and the fuel tank looks like the Kavan Flexi tank will be the one to use. We will see.

Nigel,
One servo for two ailerons is much less than half of the current the two servos would use.
All lift forces on the ailerons will be compensated!. Play of course is a problem but we have good materials to make bell cranks for example.
I do not have any adjustable quick link on the aileron connections. Simple rules for me, design the normal throw with the max displacement of the servo.
Second rule is, use lot of movement of the connection rods, this reduces the play and force in the rod. Simple rules for me.
Succes
Cees

Hi Nigel,

My wing is nearly at the ...Cut out the Aileron stage

The plan shows a 2:1 Reduction at the bellcrank [] I am not sure that this is going to be enough movement.

On my servo is a small wheel it also does not give much movement.

The plan shows the linkage going to the top hole in the horn on the aileron ....Even less movement []


Do we trust Phil Kraft and go 2:1 or go 1:1 and reduce it in the radio if the ailerons have too much movement ?

I havent messed with bellcranks before......My head is starting to hurt [&o]

I have posted photos, I used a standard Futaba 148 servo in my setup

Johnkpap