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Member postings for Jon - Laser Engines

Here is a list of all the postings Jon - Laser Engines has made in our forums. Click on a thread name to jump to the thread.

Thread: Servo choice
13/11/2018 13:38:25

a model like the pawnee does not need anything beyond standard 3kg servos. futaba 148, 3003 etc, hitec 311 etc. The savox 352 is a good servo, i have loads, but its overkill here

Thread: Saito FA40a domed nut
12/11/2018 20:21:11
Posted by Paul Marsh on 12/11/2018 19:29:39:

I would recommend to anyone using a four stroke, not to use wooden props for the reasons stated. The only times I tried doing so, each time, I had the prop smash itself to pieces when the throttle was advanced, even though set slightly rich, a nasty pinking sound just before the prop self-destructed, sending shards of wood everywhere.

So my advice: No wooden props, ever!smiley

so why is it that none of my props have exploded?

Honestly posts like this really irritate me as they do nothing other than spread completely false information. Its nothing personal Paul, but this recommendation is complete nonsense.

There is a potential for wood props to be compressed and come loose but only if normal maintenance procedures are ignored.

Running rich will also not help and may in fact cause the prop to come off due to the engine not running smoothly.

You can all ignore me if you like, but as a manufacturer of 4 stroke engines im telling you wood props are fine if used correctly.

12/11/2018 18:17:35
Posted by Alan Gorham_ on 12/11/2018 17:29:47:

It's a classic case of YMMV Jon.

I wouldn't fit a wooden prop on any of my smaller single cylinder 4 strokes after seeing what I have seen, plus I only hand start my engines and I like the flywheel effect a heavy glass prop gives.

I would/do use a wooden prop on my OS Gemini though.

im not sure what that is exactly so cant really comment. But i hand start all of my engines where possible. Its only the ones buried in cowlings that i leccy start. The wooden propped saito 45 is always hand started unless its freezing cold and i cant be bothered! Either way, my approach to wood props is simply to do it up tight and then leave the blasted thing alone. If there has been big change in temperature/humidity then fine, give the nut a tug and see what happens. Its really not a big issue though.

Percy, my dads first engine threw props all the time, the 2nd didnt. The engine was only replaced as the crankcase fell apart on the first. He suspected the early batches had something wrong but was never able to prove it. At the time others were having the same issue with the same engine, then it all went away.

12/11/2018 16:30:25

the os 48 was notorious for throwing props. My dad got through almost a prop a week in the early days when it came out. I have an OS40 that will throw anything if you arent nice to it, and my enya 53 throws props if you dont warm it up before giving it full power. In most cases, its the engine that is the issue and not the prop.

In any case i use wooden props on all of my 4 strokes over 180 size as well as on the saito 45, saito 50 and a laser 70. None give any trouble.

The heavy brass prop nut will counter any loss of flywheel, using a larger prop will help as well. Something like a 13x5 or perhaps 14x4 or 5 will work nicely on the tiger as its not exactly a rocket ship!

12/11/2018 15:36:59

I would go without the washer if its got a shape to it. If its flat then leave it.

A wooden prop will not be a problem but Alan is right, you need to keep an eye on the prop nut. My saito 45 runs a wooden prop on my nieuport and i check the nut every now and then. Its rarely loose, but i do tend to go for it when tightening it up!

Thread: Scale Nose Gear
12/11/2018 14:29:44

**LINK**

not sure about the scale

Thread: Seagull Mosquito Laser build
12/11/2018 00:12:30

same.

Mike if you try right clicking on the video while its playing and select the copy embed code option. you can then press the little youtube button when replying to a post and dump the copied info in there

Thread: Fixed or steerable tail wheel
11/11/2018 16:45:04

i have 3 models with castoring tail wheels and they are no problem in all but the worst cross winds and even then its only trying to taxi that is the issue

Thread: Seagull Mosquito Laser build
11/11/2018 11:40:44
Posted by Chris Walby on 11/11/2018 07:34:26:

I didn't want to get into a position where I needed to run at full throttle, but feared to damage the engines -

off topic i know, but you really wont break them. As long as you have good fuel and dont roast them to death, you will not do them any harm by using all of the power available.

Mike, the first video is only 3 seconds long and i get an error with the 2nd one

10/11/2018 23:13:52

Sad news Mike, i hope you can fix it.

Other than the landing stall how was it? i hope the engines were ok

Thread: Seagull Hurricane
10/11/2018 10:49:46
Posted by neil martin 1 on 10/11/2018 08:20:54:
Wish there were more videos to view of the hurricane flying. Surprised by the minimal amount of reports on this plane since it's release.

If the instructions are followed i suspect that many dont survive the maiden as the elevators are just too sensitive with the suggested 15mm movement.

I was intending to get some photo/video of Tims example but we obviously changed our priorities after the first flight excitement. If im there next time i will try and get some snaps

Thread: Out of trim
10/11/2018 10:46:28
Posted by Peter Christy on 10/11/2018 09:56:16:

If you think an out-of-trim aeroplane is tricky, wait till you have to deal with an out-of-trim helicopter!!!

surprise

--

Pete

aint that the truth!

To all the comments suggesting that more attention needs to be paid to the setup of the model i again completely agree. In the case i mention the root cause was a small error in the setup meaning the elevator wasnt totally level. This was then compounded by other factors like the excessive rates from the instructions.

Even with those sorts of things ruled out and the model set up correctly its not a guarantee everything will be fine. My Sea Fury is a prime example as it was very out of trim due to an incidence error in the design of the model. This has been well documented on RCU as everyone that owns one needs stacks of down trim to keep it on an even keel. Once trimmed like that its perfect, but the model is wrong.

This brings me back to should we practice flying out of trim? Personally i dont practice as such, but as most of my models are a mix of scale biplanes and WWII fighters its virtually impossible to trim them as the requirements change so much with air speed so i get my practice every flight i make. My P39 suffers trim changes in pitch and yaw as airspeed changes with left rudder needed at slow speed and right rudder at high speed, exactly like the full size. Add a bit of gyro effect from the long nose/heavy spinner, large roll/yaw and yaw/roll interactions and its quite an enjoyable challenge

09/11/2018 20:47:59
Posted by Don Fry on 09/11/2018 19:21:41:

Pete, this thread is somwhat cerebral at present.

Don't get us going on the relative merits of rates, and exponential .

While another aspect for sure i understand where he is coming from. If the model is so sensitive you cant fly it then its hard to trim, but equally, if its miles out of trim you cant get the rates right either. I am very critical of kit manufacturers as in the case described in my first post we started at about 75% of the recommended minimum and ended up at less than half of the recommended minimum. Even without the trim issue, using the recommended travel would have likely caused significant difficulty to anyone testing the model irrespective of the trim situation. The addition of large amounts of expo would have made things worse in this case. As you say though Don, that is another conversation entirely.

Pete, as a curiosity do you ever teach people how to fly their models when out of trim? and then show them how to trim their own models as that chap did for you?

09/11/2018 17:14:49

Thanks for the input guys

Don, 100% i agree that models out of trim, especially in more than one axis, can be an extremely intimidating thing to deal with and the stress of the situation 15-20 seconds into a maiden flight can be too much and brain overload is the result. Its just human nature and i cant fault anyone for that.

This is why i think we should all practice flying models in this condition.

If you have a model you know well, the trusty hack that you always bring out on windy days for example, why not set it out of trim, a few clicks down and few to the left or whatever. Then takeoff and go for a flight. As you know where its going to go you have half the battle won and already know the corrective action in your mind. Fly 3 or 4 laps, left and right, do a landing. Trim it so its even worse, do it again and so on. After a few flights i doubt you will have the same trepidation you feel now. Before the flight it may also be a good idea to hold the tranny, close your eyes and try to find the trims so that you dont have to take your eye off the model to find them in the heat of the moment.

All that said, the idea of abandoning the flight and landing if its too far gone is a worthy recommendation. It comes back to not forgetting to fly the model. Asking an assistant to move the trims for you in an extreme case is also not a bad idea, just dont forget to fly the model while you are giving him the instructions on what to do. If the flight is to be abandoned due to poor trim, just remember than the landing may be pretty ugly. If available, why not choose the long grass or the corn? i had a Hurricane some years back that had too much elevator travel, i knew i couldnt land it like that so i landed gear up in the crop. I had already decided to do that in case of emergency before the flight so i didnt have to actually come up with a plan while focused on the model in the air. 

Trevor, i usually give my students a pretty hard time. i give them models out of trim, i am obsessed with keeping the wings level, i make them fly in strong wind and disable their ailerons on the buddy box to teach rudder control, circuit planning, and to simulate a case of reversed ailerons where they have to get down with rudder only. They hate me for it, right up until its time for their first cross wind landing. I dont go out of my way to make it difficult, but im there to teach them to fly and not just pass their solo. Its all worth it when they finally go 'ohhh i see why you made me do that now'.

 

 

Edited By Jon - Laser Engines on 09/11/2018 17:18:41

09/11/2018 14:27:07

A recent experience reminded me of something that i have seen a great many times and it got me thinking.

Firstly, this is not a criticism of anyone and i am not trying to blow my own trumpet, its just something that came to mind and is perhaps something to consider as it could come in handy.

So, to set the scene we have the maiden flight of a new model. As im sure you have all guessed from the title of the thread it was out of trim once it left the ground. The model also had slightly over sensitive rates and the two things combined with an understandably nervous pilot gave a nice bucking bronco effect to the first half circuit. Ultimately this led to a spin which would have been terminal were it not for my intervention. I was able to regain control, get the model trimmed out and we then moved forward with getting it all set up. its all nicely sorted now.

Being out of trim with slightly excessive rates or wayward c/g is not uncommon in a new model and i am sure we have all seen models follow a similar flight path to the one i described, perhaps without the happy ending.

In these cases one of the contributory factors seems to be the apparent inability of the pilot to fly the model in its out of trim condition and this brings me to the point of this thread.

What i was wondering is how many of us have really been taught trimming, and how many are comfortable with, and/or practice flying a model that is badly out of trim? I ask as the only reason i was able to rescue the situation described above is that i was comfortable to fly the model in its out of trim condition and was able to adapt to it quickly enough to maintain a normal level circuit long enough to get the trim tidied up. This was probably 2 laps of the patch in an slowly improving out of trim state. I always teach my students trimming and 'force' them to fly circuits with the model out of trim so they have some experience of how to handle it as they will have to maiden a new model eventually. I always tell them that an out trim model is no excuse for not flying a proper circuit. In essence, fly the aeroplane, worry about the trim later.

Again the objective here is not to judge anyone or criticise their flying skills, I am just curious to hear the views on this subject as i definitely think trimming is a flying skill like any other and should probably be something we practice more often.

Thread: Seagull Hurricane
09/11/2018 13:40:55
Posted by Cuban8 on 09/11/2018 13:19:29:

Ron, by any chance were the servos Hitec? I found that the Hitec MG servos I had were very unhappy at much over 6.0 V.

JR591's

 

Ahhh you beat me Ron!

Edited By Jon - Laser Engines on 09/11/2018 13:41:22

Thread: fokker dri wing incedence
09/11/2018 11:26:28
Posted by Ikura on 09/11/2018 09:17:12:

Bert, try the following for the Fokker Triplane to fly without it being a nightmare:

Top wing: -1 degree

Middle wing: 0 degree

Bottom wing: +1 degree

Stabiliser: 0 degree

Axle fairing: 0 degree

The tail needs a significant incidence so 0 wont work. I have the smaller flair triplane and it, along with my flair nieuport, have the tail at a pretty serious angle. I really dont think 0 is a good idea. 

For the main wings, i would stick them all at 0 and just forget it. 

Edited By Jon - Laser Engines on 09/11/2018 11:27:07

Thread: Seagull Hurricane
08/11/2018 19:57:23

warbirds can be a difficult balance as the amount of elevator needed to stop the thing sitting on its nose is often far more than is needed for flight. We also fly off of a very rough surface in scale terms as a blade of grass is the same size for the model as it is for the full size. That said, most of the nose over issues i faced were down to mistakes on my part and a spot of bad luck, i dont think its the norm in the long run

08/11/2018 14:17:05

it seemed that the pitch trim changes came with airspeed and not directly from the throttle as even when off throttle in a dive the model wanted to climb. Its something we can revisit and refine later if we choose to but for now i would not worry too much as too many changes can have unexpected results.

I think its just very pitch sensitive which is not uncommon for WWII fighters as we have discussed before. One thing that might also be worth while is changing the rates on the P47 so it feels more like the Hurricane and just practice flying with very small control inputs.

we can look at it all again next time you fly it

08/11/2018 11:29:59

Im surprised to hear its nearly 18lbs, it felt lighter than that.

Not that it matters particularly, i dont think we used more than 1/2 throttle for normal flying about so power is not an issue.

Moving the horns on the elevator is a good idea. Once down to 35% on the rates it was time to move the linkage for sure, as long as the overall movement ends up the same its not going to be a problem

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