Zulu ET

[David Ashby - Moderator]

Posted by kc on 02/11/2010 17:40:25:

Lindsay I can see very well what the measurement of the incidence on the plan is, what I am questioning is whether your plane was built the same as the plan!   It seems you cannot be bothered to measure the incidence on your plane ( the one a witness said flew well ) and help the builder who said his flew badly.

There may well be other things wrong with a plane that flew badly and it is likely  a combination of things.  But lets clarify this point first.

 

Kindly note that I am pursuing this point to help a modeller who sent me several PM's asking for help on various points on this design. 

 

Edited By kc on 02/11/2010 17:49:19

 

Cool it please kc, You've made your point several times now.  

 

Lindsay tells me that he's flown the model with various wing incidence settings since these queries arose and the model flies well whatever the setting within a few degrees. Let's be honest, we're not talking patternship here. Have I got that correct Lindsay? 

 

[kc]

 It is a tradition in aeromodelling and on this forum to help others when problems arise.  Why is nobody except me bothering to try to help the person who said his Zulu did not fly well?   The designer should concern himself and see if his design errors on F5 & F4 have contributed to the problems with this particular Zulu or whether it is some other problem.

 

On most models a slight problem with incidence would be cured with a couple of clicks / beeps of elevator trim so it may not be this.  We need to eliminate this first. 

 

Even the material list in the latest RCME has errors in it!

[Kit Davidson]

"Why is nobody except me bothering to try to help the person who said his Zulu did not fly well?"

 

I think it is to do with attitude. Jet didn't ask for help. He condemned his aircraft to the bonfire. Dave W made F4 and F5 fit his construction with the wing incidence set as per the plan. I have done the same. I am really pleased with this design. It has rekindled old skills and I see it as a great start to an exciting new hobby. I thank Lindsay Todd for it. If I see anything I consider not quite right or something that does not quite fit, I modify it or think out a solution like Dave W. For instance there is some incredibly short grain at the bottom corner of the rudder cut-out. The tailwheel is attached to the rudder and will absorb the landing loads in this fragile area The designer's solution is to reinforce the cutout with a plexiglass frame and a strip of ply to the rudder base.  I have increased the area of the reinforcement to my own specification and my tendency for heavy landings! Another solution is to attach the tailwheel to the fuselage as the designer did in the prototype. Nothing is insurmountable.

 

Can we now move on from wing incidence hobby horses? Time to be less picky I think. 

[Biggles' Elder Brother - Moderator]

I agree with Kit. Jet did not exactly cover himself in glory in the manner he approached the subject and the "community" and he did not actually ask anyone for help.

 

I know Lynsay is a clubmate, and you might think "well BEB would support him wouldn't he", but I have to say I think he really has gone "the extra mile" on this one, building another example, photographing the stages and posting it all. And it seems a poor reward for his efforts to be treated in this fashion. I am sure he will appreciate your kind comments Kit.

 

Lyndsay is a very experienced modeller, if he, as the designer, prototype builder and "test pilot", says the incidence on the plan is correct and the one to use then that would be good enough for me.

 

Kit's right, move on. If Jet wants help, then, as I said in an earlier post, he only has to ask in reasonable fashion and knowing the lot on here he would be deluged in advice from all quarters - not least from Lynsay.

 

BEB

[Ron Harrison]

Can we just stop all this sniping please guys? No use getting hot under the collar over the percieved problem!

 

I thought this hobby was about Building, & Experimenting if things do not go according to 'Plan'

 

Put it to bed and move on.

 

If people wish to ask questions then let them, how else are they going to learn?

 

Makes me wonder if RCM&E are going to publish a plan in the future on how to build a 'Soapbox'?

[Darrell Bullard]

Dear Mother

As I set here in my fox hole in the middle of the Zulu incident war, I was wondering if you knew if the wing is fixed to the body of the plane once the dowl is in place or if it sets in a hole making it removable and only attached to the wing its self? I had mailed Lindsay but im getting itchy to keep building!

 

Sorry guys thought a little humor might help!

Darrell

 

[Biggles' Elder Brother - Moderator]

Posted by Darrell Bullard on 03/11/2010 15:18:05:

Dear Mother

As I set here in my fox hole in the middle of the Zulu incident war, I was wondering if you knew...

 

 

 

Dunno - but I know a man who does!

BEB

 

[Lindsay Todd]

Guy's many thanks - moving on, Darrell I have sent a pm, David you are correct - thanks one and all, can we play nicely together now please.

 

Ply blocks are mounted in the wings 1.5mm off the underside surface, spaced to accomodate your chosen servo, in this case Hitec HS81's.

Turning the wing over shows the 1.5mm sheeting arond the servo bay, it make the covering a little neater I think.

Wing centre  section has now been sanded and scrap added to close up the gap to the front, dowel has been added and a ply facing for the wing bolt. Now for the covering.

Not quite enough yellow solartex so we are going green and yellow, amazing what you can do with off-cuts - throw nothing away it'll always come in handy.

With tail plane and fin covered, dry fit and check for square, mark the covering lightly and then trim away so that when glued you have a good wood to wood glue joint, when happy glue in place. the horns can then be fitted, nothing special here just standard comercial items used. Forward strake is just  soft balsa sheet sanded, covered and glued to fuselage and fin.

Servos can now be mounted, this is my set up for this model, note the model is large enough to take a standard size servo, in this case to elevator.

Darrell this might help re wing dowel.

 

Next job is to fit a motor - just ordered a 320watt outrunner, little larger than prototype as it will also be useful for future projects.

 

As a point on the tail wheel, the plan does show a wire to the rudder, this was not on the original design and I would not recomend this. I use a castering item and elastic bands through the rudder / elevator appreture as this reduces strain on the system and has worked very well. Its one of the next jobs to do so will photo.

 

more soon

 

Lindsay

 

[Jimbo565]

Little larger than prototype !!!!!!!

 

I know someone else thats done that.

 

Homesick angel springs to mind.

 

JImbo 

[A.A. Barry]

Lindsay, very nice

A.A. Barry

[Lindsay Todd]

Jim, you were my inspiration matey

[Joe Hull]

Just returned from Hol last night thanks Kit for your post.

 

I am very new to all this, my board is only 32inches by 24 inches made with some left over cork floor tiles. I don't have much space in my garage so I have to be tidy because there is so little space.

 

Thank you also to Jim for shoing us his hinged door idea, I like that I think I may copy that idea seems sensible to improve access for replacement of servos etc

 

I glued the hardwood blocks in this morning so will soon be onto enclosing bottom of fuselage. I am wondering whether to fix the rest of the  sheeting under the fuz using plastic screws to remove if neccessary to get at snakes etc

 

 

[Jimbo565]

Joe,

 

No screwed on sheeting,the bottom sheeting needs to be glued in place,if you supprt the snakes a regular intervals with scrap balsa and epoxy, the bottom sheet will never have to be removed.

 

I hinged my access hatch with covering material and it work well.

 

Jim   

[Joe Hull]

Ok Jim thanks.

 

How do you secure the free end opposite the hinge?

 

Won't the material at the hinge end eventually fracture by being flexed a few times?

 

Joe

[Jimbo565]

Joe

Just a piece of 1/4 square hardwood glued on to the cross member and a small screw through the hatch into the hardwood,if you look at the pic you will see the 1/4 square glued to the cross member.

 

Solartex will not tear that easily.

 

Jim

[Kit Davidson]

Joe - I have used the Solartex as my aileron hinges.

[Kit Davidson]

For readers who are interested in my progress, I faced my first setback today. I had mounted my aileron mini-servos on double-sided tape. On the first functional check after mounting the wing, both came adrift. I won't do that again!

 

My tailplane and fin assembly has for some reason that I don't feel the need to investigate, a 10mm gap between it and the tail cone. Perhaps it'll give some extra leverage during flight, although I fully intend limiting control surface travel and programming in lots of exponential.

 

I have yet to fit an ON/OFF switch, fix the unstuck aileron servos, fit the cabin windscreen and make those little fairing blocks for the tailplane/fin junction. Oh yes! I think this model needs an intake grill. I can't finish tomorrow. The sun is programmed to shine and I feel the need to get slope soaring with a new glider. 

Edited By Kit Davidson on 09/11/2010 18:50:52

[Joe Hull]

Thanks for the info both Jim and Kit.

 

I have fitted undercarriage blocks and plate and stuck 3mm balsa sheet from rear of F4

to rear lattice this evening.

 

I have decided afterall to fit the servos a la Lyndsay method from the top but I may use a hinged door for battery compartment so information still useful thanks.

 

Joe

[Joe Hull]

How do you fit and get at the electric motor to change it, should the need arise, once the top cockpit deck is fitted?

 

Is this easy once the battery compartment is fitted?

 

Joe

[Kit Davidson]

Whoa there Joe! When you say electric motor do you mean rudder and elevator servos? The electric motor for propulsive power is easily accessible in front of frame 1. If you remember my posting of 25 October and Lindsay's reply of the same day, I was worried about sealing in the space in which the rudder and elevator servos were to be placed. I imagine this is still your problem. Lindsay used the space immediately behind frame 2 for the prototype but he subsequently recommended the large space between frame 3 and 4. This is the cabin and is easily reached from above or through the still unglazed cabin window. I actually made a servo tray behind frame 2 and was prepared to fit a hinged door for access in the bottom of the model. Then I thought some more about it. I opted for the cabin solution and my redundant frame 2 servo tray is still underneath the cabin decking. There was little point in removing it. I made a new cabin servo tray out of liteply and mounted it on 6x6mm bearers. I am just going out to my workshop to take a photograph. Standby! Watch this space in 15 minutes.

[Kit Davidson]

Here is my servo tray Joe. It has a slightly different layout to Lindsay's. It is made of 2mm ply reinforced with 6x6mm balsa beneath. It sits on 6x6mm balsa bearers stuck to the cabin sides with cyano glue. I cut the holes in the ply for the servos with a fret saw. The receiver is held with a sticky backed velcro patch. You may also notice that I have restrained the snakes with blobs of epoxy through holes in frame 4 and to the underside of frame 5. The servos were £4.99 each from Whitchurch models in Shropshire.

Edited By Kit Davidson on 09/11/2010 21:26:50

Edited By Kit Davidson on 09/11/2010 21:27:43

[Joe Hull]

Thanks Kit for the photos - gives me a better idea of how to fit servos and receiver.

 

I did wonder how enclosed the outrunner propulsion motor would be, once installed, and how accessible it would be if it needed to be changed at any time.

 

They seem to be reliable but I am worried that they may not be easy to remove and change if required.

 

My build is quite slow, I am still on the fuselage. The plane will probably not be ready to fly until sometime in 2011.

 

Your servos are cheap, are they Hitec 81's?

 

Joe

[Kit Davidson]

Joe - The servos are made by Etronix. Here is their page on the Etronix web site

 http://www.etronix-rc.com/etronix-9g-micro-servo.php

[Joe Hull]

Thanks Kit for the info.

 

I have done likewise with servos - I have created a platform with 3mm Lite ply reinforced with hardwood bearers underneath.

 

I have been thinking about the battery compartment .I have created a larger battery box right across the width of the fuz for ease of access and I will probably locate the ESC here as well. Should also be able to get reasonable access to screws securing motor in place.

 

I propose using velcro to attach the battery to the patform and then enclosing the battery by creating a  hatch or cover which will either be hinged at one end or screwed down at both ends.

 

I use a similar arrangement in my Seagull Innovator trainer and it seems to work Ok

Edited By Joe Hull on 14/11/2010 14:57:58

Edited By Joe Hull on 14/11/2010 15:00:28

Edited By Joe Hull on 14/11/2010 15:04:07

[Lindsay Todd]

Just remember to put some holes in the plate for cooling. Having some problems with my liitle camera again so zulu photos need to wait. Can report the on-line build version flew yesterday - all fine. It has a larger motor at 320watt throwing an 11x5 prop at 1200 rpm, it needed a couple of clicks of down trim for fly straight and level. This time it is solartex covered so a little heavy than original. I will upload remaining photos and some video when time / weather allows. 

Lindsay