Artto Ilmanen
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Posts posted by Artto Ilmanen
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This is my ESM air valve (at least I think this an ESM one)
This thing just has 2 O-rings doing the job - no spring whatsoever. I tried to apply grease but no help. Maybe new O-rings could help, I dunno..
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Thanks Jon,
Mine is leaking very bad - the pressure drops from 80-90 psi to about 30-40psi in 3-5 seconds. If I wait for 30 seconds I barely get the gear up.
I’m using the standard ESM air tank which is smaller than the Robart one. But, I believe it’s ok as long as I get the leaks (air valve) sorted out so the gear performs in a manner as you write
If I can’t fix the ESM valve, then, what might be options for replacement valve? a Robart blue valve?
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1 hour ago, Artto Ilmanen said:
I just installed ESM air retracts on my ESM Focke Wulf 71" - at 85psi plenty of power to operate the gear even with the original ESM wheels that are quite heavy. But, I seem to have some leaks so I need to sort them out. I already moved the air tank from the fuse on the wing so I was able to get rid of the air connectors between the fuse and the wing (another source for leaks). Anyways, carrying out maintenance of the air cylinders is ok but can you do anything with the ESM air valve? (see picture)
Or, are you gents replacing the ESM air valve with a more quality stuff, such as Robart air valve etc?
Ok, I tested the system for leaks and it is the air valve which is leaking. I need to dismantle it and see if it can be fixed. Or, alternatively, I need a replacement air valve
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On 24/08/2022 at 11:35, Jon - Laser Engines said:
My YT La7 is over a decade old and has suffered 3 or 4 retract failures in that time, all in its first 5 years of use. One was a servo failure on the operating valve and the others were loss of pressure due to dirt in the filling valve and my pre flight checks now check this more closely and i now catch the problem before i fly. In all cases a belly landing was performed with a minimum of damage, often flying again the same day.
Air retracts get a load of bad press due to leaks/failures but as with most things in this hobby correct installation and maintenance are essential.
In the case of my YT models and any retracts originating from china i strip the units down, clean them, grease them up and put them back together with threadlock and test them for smooth operation. Once in the model i gas them up, wait 5 minutes, retract the gear, wait 15 minutes, and then lower the gear. If they come down nicely they have passed the leak test and its off to the field. I know some like to leak test their retracts for hours and my only comment about that is why? A flight is rarely more than 15 minutes and as long as you have enough air pressure to get the up locks out gravity will do the rest.
I am also not worried about a gear up landing. Its inconvenient, but not something to be scared of and its very unlikely to do major damage. If you watch youtube videos of people doing gear up landings you will see a large number would be considered awful approaches even if they had wheels. I think people get in a panic about damaging the model and their flying suffers as a consequence. This usually manifests as being afraid of the ground, trying to flare too high and then stalling causing the model to thump onto the ground causing more damage than landing normally. Just accept that its a gear up landing, shrug your shoulders, and land. I tend to kill the engine once i know the runway is made and just before touchdown flick the flaps up to prevent damage.
Anyway i like air retracts and have them in 4 models currently with at least 5 more that will have them in future. I have one set of electric retracts in my sea fury and they have let me down once in its 8 years of service. They are more of a faff to use and set up though but the main issue with them is the controller is a bit donkey. Some decent electric retracts from electron are likely to be ok and i will probably get some in future to try in one model or another.
Certainly i would take a cheap set of air retracts over a cheap set of electric ones as most ills in an air retract can be cured with a clean or a new O ring or something. Trying to sort out a half dozen tiny brass gears is another story.
I just installed ESM air retracts on my ESM Focke Wulf 71" - at 85psi plenty of power to operate the gear even with the original ESM wheels that are quite heavy. But, I seem to have some leaks so I need to sort them out. I already moved the air tank from the fuse on the wing so I was able to get rid of the air connectors between the fuse and the wing (another source for leaks). Anyways, carrying out maintenance of the air cylinders is ok but can you do anything with the ESM air valve? (see picture)
Or, are you gents replacing the ESM air valve with a more quality stuff, such as Robart air valve etc?
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On 17/01/2020 at 22:10, Jon - Laser Engines said:
looks great to me. On all of my ESM/YT models i have ditched the plastic wheel wells and just painted/fuel proofed the wood. Why? Well the plastic things supplied are a total pain to fit. They also fit the wheels/legs so tightly that any slight tweak means the gear wont retract. The final one is that most WWII era fighters didnt hav sealed wheel wells. The BF109 had canvas bags to seal them, but most were just open structures so leaving the plastic liners out is actually more scale.
Truthfully though scale considerations are lower on the priority list and i mostly do as Ron has done as it saves so much work.
Have you Jon experience any issues such as balsa covering stripping of due the airstream? Or any strange flying behaviour when gear down due to open structure causing some turbulence (potentially?)
extract what Ron's wrote: "..the wells themselves need work to them as they are just an open structure and my concern, if flown like that, would be the slipstream getting inside the wing structure and possibly blowing the covering off."
I'm not using the plastic wheel wells with my WSM Focke Wulf due to the very same reasons: more scale without them and they do not fit well in anyways. I'm tempted to save some weight & work and just paint and fuel proof the open structure.
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On 23/09/2021 at 17:09, Jon - Laser Engines said:
5/15x24 unf or m8x1.25 depending on age. My bet would be m8 if the 10 years is accurate
Sorry Jon - I believe there is a typo here and you meant 5/16x unf? ( as we spoke on the phone?)
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Ok, thanks for everybody for the hints and sharing experience.
It seems that both OS and Laser 155 have longer prop threads than Laser 150. With a Laser 150 the single dome nut might the most straightforward way to go as Chris pointed out earlier.
I try to ensure the dome nut, whatever I buy, is made of good quality aluminium and not from the most cheapest and softest chinese stuff.
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Thanks Chris,
Sounds promising. I have never used a lock nut with Laser engines and I have never had any issues. The only thing that was puzzling me is the dome nut is of aluminium and thus less capable to take stress of tightening the prop vs a steel nut.
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Jon, Gentlemen,
I'm learning something regarding dome nuts - maybe this is of interest for other Laser enthusiasts, as well:
I want to have a dome nut for my Great Planes Super Chipmunk and Laser 150 so I contacted Sarik Hobby and Just Engines. It turned out Just Engines have 2 options:
- one option is to use a dome nut that can be recessed so steel propeller nut + washer can be used to secure the propeller in place: The dome nut is recessed so it just covers the single steel nut (5mm or about 4 threads left to tighten the dome nut):
- the other option is to leave out the steel nut and secure the propeller with a washer + dome nut. In this case 11mm of thread length left to secure the propeller - and no recess of the dome nut (as no steel nut to cover)
hmm.. could one of these alternatives work? Also, when an electric starter is being used? Which might be the best one?
Some pictures of the propeller axle thread lengths with and without a steel nut
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Thanks Phil - this all confirms what is said earlier: safe to use unregulated Life with standard 6V servos
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7 minutes ago, Don Fry said:
Ask the manufacturer. I suspect very strongly the answer might be polite, when the thought process will be “why on earth produce two products to do the same job, in the same aircraft, same air, on different sides of a puddle”
This is what one thinks - yet I have experienced this fenomenon when I was looking at some boating accessories. Don't recall any more the details, though.
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Thanks, Richard!
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8 minutes ago, Richard Wills 2 said:
I swapped to the Hitec HD switch once the Futaba one was discontinued, happy with them so far.
Thanks Richard,
is this what you are using? The Futaba HD switch is capable to handle quite much current - and is very reliable
Is this similar?
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2 minutes ago, john stones 1 - Moderator said:
Always believed Life and Nimh had similar characteristics re voltage, Nicads a different story.
John,
you may be right - I’m happy to stand corrected
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3 minutes ago, Don Fry said:
Artto, you have two conflicting statements.
1. Shop assistant in Steve Webb.
2. Manufacturer.
your choice.
Don,
Very true - I just do not know if the product range is the same here and in the USA: hence my hesitation.
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By the way, it seems the genuine Futaba HD switch that I used to use is discontinued.
Ant hints for a good quality HD switch? ( I happen to be preparing an order at servoshop.uk.co so I might add few switches to my order)
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thanks for you all,
From what you write it seems it’s ok and should not cause any premature servo failures.
I think the counter-argument I have heard is based on the LiFE battery being able to maintaint the voltage better than a Nimh pack.
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1 minute ago, Richard Wills 2 said:
Yes I have used savox with direct Life packs no problems. The voltage of a 6.6V life is lower than a freshly charged 5 cell nimh anyway.
Thanks Richard,
This is what I have been thinking, too. But isn’it so that a 5 cell NiMh battery voltage drops very quick below 6V when loaded while a Life pack stays above 6v for most of its capacity, even when loaded? Is this something to consider ?
Or am I wrong and thinking too complicated?
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Gents,
Have you first hand experience with powering Savöx 6V servos with unregulated 2s Life battery?
I came across this at https://www.savoxusa.com/pages/faq :
"Our 6V rated servos can handle power from a fully charged 2S LiFe pack without any issues. However, you will need a regulator for 2S LiPo operation."
->
However, not really knowing if the product range is the same in the USA vs. Europe I asked the the topic from Steve Webb (servoshop.co.uk)
This is what I was answered:
"Savox 4.8-6V servos are not designed for use with a 6.6V LiFe battery, you would need to use an in-line regulator to reduce the voltage to 6V."
Well, I find this a bit confusing.. ?
Anyways, I can, of course, forget the whole matter and use a sub-c 5s NIMH battery pack but it weights around 300g and a similar capacity Life pack weighs maybe 100g less. Also, I believe I do not need to maintenance cycle a Life battery pack but instead I can just charge it full and leave it there when I'm not flying (winter time) without any issues in terms of ruining the battery pack.
Or, I could buy a crazy expensive "safety switch" with build-in regulator. Yet I have flown years using just good quality HD switch(es) in conjunction with quality battery packs.
So I think the optimum setup for me would be just a quality HD switch and a Life battery powering directly (unregulated) the Savöx standard 6V servos to avoid any complicated issues.
So, can I use the Savöx servos with unregulated 2s Life? What do you think? Any first hand experience?
thanks! 🙂
Artto
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Very well - I too was thinking of the scale exhausts for exiting the air but let’s see. However, the air inlet is also a matter to be considered. The scoop in the full size one seems to be too far below the wing to help with the air inlet.
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By the way, Jon
How are you planning to organize the cooling in your model? Decent baffling of course but ideas for air inlet and exit?
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Jon, what do you expect, how much your painting job is going to add weight?
I'm asking as I have been offered a YA Spitfire for 150€ and I'm tempted to buy as at least where I live you do not come across these often.
No crashing but the model requires rebuilding as it looks ugly etc. But no fractures or cracs on the fuselage and the wing is also in good shape without any major accidents. Also, the bottom front part of the cowling is missing.
The original builder just sanded sanded the wing and then painted and varnished it - no glass cloth whatsoever and the work was done very poorly, unfortunately.
Anyways, the model now weighs 5600g without servos, tanks and engine + plumping, electronics, spinner, etc. Also, no pilot included in the weight. My maths shows it could weight in ballpark of 18lbs when ready to fly (how so little, maybe I need to tweak my math?). But, if I cover the wing with light glass cloth and then paint the wing I certainly add weight - but the question is how much? Any ballpark idea? I'm not experienced with this kind of painting projects.
I'm still planning to mount the 240V if I can keep the weight at this ballpark..
Few pictures to motivate you - as yours looks so much better 🙂
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thanks, Jon
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On 18/01/2023 at 13:26, Jon - Laser Engines said:
The first FT-310 prototype was fired up just now and the performance was slightly above my expectation. I wanted 8000 on an APC 20x8 but the little beasty gave me 8200 peak and 8000/8100 steady.
No video im afraid as i nearly lost a finger to hypothermia in the propeller slipstream and had to not only cut short my run plan for the 310 but abandon my plans to catch up on engine running until we get a bit more warmth.
Anyway, things are starting to move.
This is interesting!
Is the FT310 bolt pattern going to be the same with the 300V?
I don’t recall the rpm of my 300V with a 20x8 so I wonder if the FT310 falls somewhere between the 300V and 360V in terms of power & ability to turn large props?
How is the weight of the FT310?
Retracts
in All Things Model Flying
Posted
Sorry Ron - not being a native speaker I may have used a wrong word here, although I do have seen others using the same word for the valve that controls the gear system. Anyways, the air control valve I’m having is causing issues and I wonder if it is worth the efforts to fix it or should I just shop a new better quality one (which?).
As this is my first air retract project I’m pretty much in learning phase