"L"Plate

Interesting Peter, I recall trying the second version (but without aileron and reducing throttle after rotation started) with a Zlin 50L but it only working one way, I was told by the owner that it was easier one way than the other due to gyroscopic action from the prop, when I tried it with my 1/4 scale it refused to spin about the lateral axis or keep the low wing pointing at the ground, it was more like a flick roll at the top of a stall turn, I tried different aileron and throttle combinations to try to get the knife edge spin but without getting it right. Anyway on with the proper stuff.

I know it is not on the F3A list but I have never got a model to Lomcevak possibly due to a lack of prop weight, but if there is a trick to get models to do it let me know. I do think the list will get most up through the first couple of levels.

Hi Stephen, The Hangar 9 Tribute 36 looks like a great fun aircraft for 3D and probably even "Fun Fly" style flying. It will not be easy to do precision aerobatics as it is fairly short in the fuselage and has big control surfaces, it is not an F3A style aircraft. That said if you are just starting out, once trimmed it should be capable of "The Book" and build your confidence up. If 3D is what you want to do I would think it is a good starting point. I can see you having a grin from ear to ear if you set the ailerons as flaperons and have a switch to mix them with elevator, I had a Wild Card (similar idea) and it could loop so tightly it got buffeted by its own wake. I did come 6th in the RAFMA aerobatics comp one year with it after crashing my Smart Move 40.

Hi Kevin, Don't worry about contradicting me, I am only going by my experiance, my jocker from the 80's seams far less effected by cross wind gusts than my Monolog. In a constant wind I would agree with you completly but in gusty conditions the Monolog needs far more correction to keep it on line, that is my experiance. My reasoning is that due to the larger side area a greater side force is imparted onto the airframe therefore overcoming more of the momentum and so moving the model further off line, mind you it could also be to do with the airframe weight. I have found in none gusty conditions little difference. Is this also your findings?

A comment on another forum got me thinking. Modern F3A type aircraft have a lot of fuselage side area, this helps a lot with the combined rolling and looping manoeuvres found in the top competition schedules, the down side is they are effected more by cross wind component in blustery conditions. All models are a compromise and we as pilots have to learn to cope with the short falls in the design and we can only do this by practicing either the manoeuvres that the airframe is not so good at or in the conditions that cause the most problems. I practice in conditions that a lot of club pilots don’t even consider worth get a model out of the car for, I think I learn a lot trying to keep a loop round and on track in windy weather (I have yet to master it).

I am with a the majority when it comes to the fibre glass prop’s as the take on water into the resin and this causes micro fractures with temp’ changes, also the resin becomes harder which makes it brittle. Now the wood prop’s I would use but only if: they balance, they haven’t split or more importantly warped. I have some 40+ year old wooden prop’s that I use on my CL models but I don’t rev the engine to the max. Mind you as IanN said “I wouldn't stand in front of or to the side of it when running.”

Hi Paul, I would definitely replace the switch, they are so cheap compared to a model, as for the retracts new air pipe shouldn't be too much of a problem, as you say the seals might be past their best in the retract units. I have some spring air retracts that are of the same sort of age and they are still working but with my new builds I now use electric retracts, they appear more reliable and fit in the same space as the old air retracts and only need servo leads running to them. Come on you have to get it back in the air, a model actually for the classic period. I wish my Merlin was in a condition that allowed refurbishment but it is past that.

Very nice classic 80's. Like the cockpit and cowl. If you can drill into the ply doubler fron the inside then use slow CA and clamp it you might get around the delamination. I would think it would hold together Okay, it tends to be engine firewalls that suffer the most with fuel soaking; if you did a good job on that when you first built it (and looking at the photo you did a good job on the rest) than that should be fine. Good luck with the air test. I am sure you wouldn't do this (other might), but I have been told of others who have not changed RX switches on test such as this and had problems with the old black wire even some chap who thought the batteries would still be good, shame two old models lost from the accounts I was given.

Well with that structure it should be fine to fly as soon as you de-wrinkle the covering. Sounds realy interesting, I always love own designs as they often depart from standards or fashion of the time and help to test ideas (good or bad), always an oppertunity to learn.

What model is it? Is it open frame structure or foam wing? Post a picture Paul.

Just a quick one, in the RC Model World there is a series on trimming for aerobatics part two is in the current issue. It is by Jon Tappin and he is going through trimming a Vanquish but he supports a lot of what has been said here. I have to say I don't have a mentor to help me out on a regular basis but I do have support from a top chap at a club a few miles away (thanks Peter for setting that up). I get around the problem to a small degree by having the chaps I am teaching to fly call for me and look at what I am doing, they think it is fair as we all get an equal share of flying. When I am training I encourage learners to do some basic aerobatics fairly early on to help them get used to seeing the aircraft in different attitudes, I also put the aircraft into different manoeuvres and hand control over to them to rectify, this I think is one of the biggest benefits of using a buddy box, I have even helped pilots after their “A” with buddy boxing for inverted flight training. I am sorry to say that most seem more interested in going on to large scale rather than aerobatics, I think this is to do with the shows as much as anything, as at most shows I have gone to recently have had about 95% of the flying being large (or very large) scale models, or jets; going back to the 70’s and 80’s there was a lot more aerobatics and demonstration flights of normal sports models.

I have flown trainers that are that old and pulled some "G" with them. The PVA glue appears to stand the test of time, the CA of that time though is less predictable as is the epoxy. If it is film covered it might be worth removing it and using some fresh CA and check it out before recovering. I have found the old film after being stored for some time and exposed to sun light tends to separate from the glue/colour fairly easily especially along the edges and the outer clear film gets a bit brittle.

Hi Steve, Now these are the setting I have on my Angel 30e, that suit my flying I made new aileron horn 30mm from surface to connector and a elevator horn 25mm from surface to connector, out of 1.6mm G10. High rate: Aileron 18mm (10% expo) Elevator 20mm (10% expo) Rudder 35mm (0%expo) Low rate: Aileron 10mm (0% expo) Elevator 12mm (0% expo) Rudder still 35mm (30% expo) CofG 3mm behind the wing joiner tube, it is smooth with the CofG in this position and spins well but will drop a tip if flown too slow. She needs just a breath on the elevator when inverted but I would suggest using a CofG in line with the back of the wing joiner tube.

Steve, I will try to measure the throws for you tonight and let you know exactly what I have on my Angel 30.

Hi Steve, Some true words. It is a state of mind with any form of aerobatics as to what you are comfortable with and to some degree the risk / price of a crash can hold you back. I am happy inverted with my 450 helicopter but get a little more twitchy with the 600. I have an Angle 30e a great little plane that will do the book, the only down side I found is the duration in any wind. I used it at the NPOD and have flown it in winds of around 20mph without too much problem, just restrict the flight time to around 5mins in the wind. If you set it up with about half the movment on the elevator and ailerons it is smooth. Do use a good servo on the elevator and I would recomend extending the elevator horn and you will still need to come in on the servo arm, to get good elevator resolution and reduce the movement, once that is done it is very nice to fly. My one has now got over 22hrs flying on it, hope you enjoy yours as much.

Well Peter, I tend to be with you about flying low inverted. I think it is to do with my days flying full size but I always fly at a hight, that should the fan stop at the front, I can at least get upright and turn into wind before arriving on the ground. Flying inverted is down to practice, so if you set part of each flight to inverted practice, you soon get to a point when an inverted circuit and then figure 8 becomes comfortable (if not normal). Just keep some safe height, I have payed for showing off low level (for a dare) and the very reliable motor picked the moment I was just a foot of the ground to stop and the one point (fin) inverted landing ended with a re-kitted airframe. It was a tatty aircraft so I didn't cry over it and would not be tempted with any of my current fleet.

I agree with you Peter, but I thought I would see what happened with my model as I am happy with the CofG and compare it with the 3D trim check method given, I expected the model to pull up but it didn't. I think the only advantage of the dive is that power / thrust line is taken out of the equation and that you can then rectify that later, it reminds me of the test that competition aerobatic slope gliders used. Hi Stephen, don't panic just build up to it at height, no need to scrape the fin on the ground. If you are getting it upright every time you must be doing something right.

Hi Terry, The CofG is 38% cord at the root but that might not work for you. On the 110 there is a cross piece above the wing joiner tube and that is the position in the insructions for it to balance, I have mine 5mm behind that. looking at the 70 manual it look like it should be just in front of that cross member, which would be the safe start point and then move it slowly back a mm at a time until you are happy with the model. If you follow the trim system Peter has layed out here in order you should be right on the money. Have a look at this link on the GBRCAA site on the Monolog 70 http://www.gbrcaa.org/smf/index.php?topic=2894.0 It is hard on your own but I think you will get a lot od good advice here.

Hi Terence, I have the Monolog 110 on 8S. I have the CofG 4mm behind the recommended position and the control thows reduced to around 75% on elevator and aileron using longer horns but left the rudder as per instructions. It is smooth and flies very well on less the 1/2 throttle with endless vertical and a duration of over 11mins and very clean needing very little mixing. It flies better than me!

I was reading a magazine at the weekend that had an article in it about 3D aircraft trimming for CofG. The method given was with the aircraft trimmed for level flight climb and then descend at 45deg and see it the aircraft tried to: A) Level off CofG too far forward. B) Stay on 45deg line CofG correct. C) Dive down CofG to far back. I tried it out on my Monolog which I have already set the CofG on and it flew straight down the 45deg line, so I feel that this is probably a reasonable test. What do you think?

I would add to Charles' post which I agree with full, try to work on one thing at a time, only change one thing at a time (that way you know what did what) and stick to one aircraft (well one for improving your aerobatics, you can have a fun hack to relax to) as no two fly the same. Indoor flying and sim's are good but not the same as flying a pattern aircraft to my mind; they do though, help you learn as lot, that can be adapted to outdoor aerobatics.

Thank you Peter and Martin for you input, you both match my thoughts and that helps me feel more confident that I am on the right path.

Thanks Martin, You are right about the mods and I have tried a lot of them (some with the advice of Mr Prettner) and that was exactly what i did (over did) with the model a talked about above. It is good to talk about these as a lot of model fliers today just use a mix. I still build models and play with designs by changing dihedral (easy on foam core wings) and other things like rudder rake. The question I was more about is there a better way to check the rudder effects, in the old days knife edge was harder with the shallow fuselages we had and I used to fly control line circles to see if the model piched or rolled with the rudder input, now with the deep fuselage I tend to do both control line circles and knife edge flight to see. The trouble is with the modern plug on wing it is a lot harder to change dihedral on the mainplane.

Yes I use mixes to try to eliminate rudder effects on roll and pitch and normally use the knife edge flight as a test but I have found on some models that the mix needed changes with speed (I assume due to the side slip airflow component), so I fly the knife edge at the speed I would fly the roll at. Is there a better way?

Thanks Peter for your answer, you may well be right about the rudder input in Mode 2 but the reason I do it was I noticed it when I flew Mode 3 but it seams more pronounced now in Mode 2, which your idea would support. I have had another thought that it might have been due to the anhedral on the model I had back then and the rudder would had a slight roll action so in the first 1/2 roll the different amounts of rudder are all act with the roll in the second 1/2 they would all against to the roll rate, unlike a model with dihedral such as a trainer which would be the opposite. The model was a pattern ship but I can't remember which one but I do remember we had changed it from a flat wing to anhedral to try and reduce the yaw roll coupling (which we slightly over did).