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Trevor

First petrol engine

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After all the talk of petrol engines, I decided I just had to try it. I bought one of these on ebay. Btw, it comes complete with ignition and standoffs etc. Now I just need a plane to try it out on. Thinking of the 96" BlackHorse J3 Cub. What do people think of this for a start in petrol flying?

 

I prefer the Black Horse Landscape 30cc but I think it might be too fast for our field.

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Nice one Trevor.

 

Will you be able to bring it to the field after you get it?

 

:D

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Congratulations! Certainly 1/4 Hangar 9 cubs have flown nicely at our field so don't see why the Black Horse one wouldn't.

 

I always thought the Black Horse Fiesler Storch looked great for that engine and the short field operations on our runway. It is a bit more pricey, but nice model.

 

Fiesler Storch

 

Martin tells me that plane was able to "hover" (zero ground speed) in right winds and was the subject of a couple of daring escapes by spies. Perfect for Fickleshole ;)

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Yes, the Storch looks lovely but it is expensive and as Geoff says, a bit heavy. That Landscape is very tempting though :)

 

Sent from my MB525 using Tapatalk 2

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Oops, never did check the weight ;) Agree the Landscape looks nice...

Edited by Guest

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Nice.......

 

Funnily enough, in between the showers I ran up my Edge 540's Zenoah 26 today to give it a full heat cycle, as not used for many months. First spin of the starter and there it sat idling and throttling nicely as usual.

 

One point I have seen mentioned is that Walbros do not like being left idle with petrol in them, it is said that it knackers the diaphragms. I drain the tank completely after a run and run the engine out of fuel anyway. This also acts as a second line of safety over the kill switch as if someone decides to test its compression and the switch is on it won't kick, not that of course YOU would slip up like that............. :wink:

 

There are a few bargain DLE 30's around currently, but I may be getting a DLE 20 shortly for a Zlin L50, a combo that is well inside the weight limit all up.

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in actual fact braveden you shud leave some petrol in the tank as if you drain the tank completely the diaphram will dry out and split

 

This appears to link the tank level with the carb having fuel in it, which is not necc a given with planes when not being run, esp if you store Fus's hanging prop up as some do.

 

Leaving fuel in the carb was also not my understanding on balance from lots of reading when I first got a petrol engine with Walbro Carb and did some research on best practice. OK, so there are arguments over this it seems, and the following sometimes leaves storage to be defined by the user, however...................(my emboldening)

 

 

From Helifreak, written by a technical person who has contact with Luis Salas, who wrote the Walbro Manuals

 

"My Best Advice

 

First

 

Unless you fly your model every day, when you're done flying remove all the fuel from than tank and using the primer bulb pump the carb as dry as possible"

 

 

Useful thread in many other ways, too.

 

 

http://www.helifreak.com/showthread.php?t=326599&page=3

 

 

 

From the Zenoah Engine Instruction Manual (Walbro Carb equipped):-

 

"For storage, make sure there is NO fuel left in the tank or the engine"

 

 

 

 

From the American Model Airplane News (where gas engines are MUCH more common than here), talking specifically about gas engines, and written by the Chief Technical Editor.

 

"If you are going to store your model, drain the fuel tank and then run the engine to burn up the fuel left in the fuel lines and inside the carburettor."

 

 

 

 

I quickly found three "heresay" references to Walbro themselves stating to drain the carb if not in constant use, have not found confirmation on the Walbro site, but then their Tech Tips are less than comprehensive (understatement!).

 

 

 

 

From a Walbro help page:-

 

 

Typical Walbro Problems

 

They're really quite reliable, but when problems arise, they are frequently one of these.

 

The small filter on the fuel-intake side clogs. Clean it out by removing and spraying carb cleaner through in the opposite direction of normal fuel flow. Re-insert using a pencil eraser.

 

The float diaphragm degrades and reap havoc on tuning, especially the low end and idle.

 

The internal needle valve WILL leak when they get old or worn out. If you notice gas dripping from your carb, or if the idle gets unreliable, replace the needle valve and adjust the lever even with (or slightly below) the carb housing if you don't have a gauge.

 

The fuel pump membrane gets stretched and/or sometimes hardens from the gas. It needs to be replaced occasionally. If your pump doesn't pump properly, (1) it will be hard to start (2) it will tend to run lean, and opening the needles won't help much if any.

 

Erratic idle, or no idle is often traced to a bad internal needle valve, bad float diaphragm, bad pump, and most common... crap in the carb. You may also have an air leak!

 

The pop-off pressure is out of the normal range. About 12 PSI is normal. Pop off pressure is how much pressure is required to pop the main-jet needle off of its seat. The fuel pump pushes fuel against a spring. Either having the wrong spring, a cut spring or stretched spring can affect this pressure.

 

All Walbro carbs will run in any position, but they tune "best" as a side draft carb meaning the airflow intake is horizontal. The down draft position tends to run a little rich at idle, and the updraft tends to run a little lean at idle although it's easily tuned regardless.

 

Seems to me there's a lot more "drain it" advice out there than not, but happy to be shown otherwise. As the saying goes, "40,000 Frenchmen can be wrong"............... :mrgreen::mrgreen:

 

History...........

 

I work with very old petrol engines all the time. Most do not have fuel pumps (they use direct gravity feed or via an Autovac and seals are metal to metal) as they could not devise a diaphragm material back then that would stand up to contact with petrol long term. It is still a lurking issue today. You don't often get this problem with cars now as even if they have a carb (most do not) they are developed designs that are not diaphragm type. The reason for the diaphragm carb is that it works in all orientations, pretty much essential for a plane!!

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THAT MODEL WOULD BE TOO HEAVY FOR OUR FIELD IT GOES 8.1Kg

Geoff

 

i disagree geoff the specified flying weight is only 5kg all up if putting a dle 30 will push it past 7kg i would be greatly shocked

to put the model over 7kg the dle 30 would have to weight 3kg on its own where with the exhaust and ignition it only just tips 1kg

 

maybe the maths need to be checked on this one

 

i think there no need for concern with this one trevor with regards to the weight

 

Yup, def a maths check needed................I think you are at cross purposes, Geoff is talking about the last model mentioned, the Storch, which is:-

 

Specification

Wingspan: 2850 mm (112")

Length: 1910 mm (75")

Weight: 8.1kg (17.8lb)

Servos: 6 x 6kg, 1 x 3kg

Radio System: 5 - 6 Channel

Petrol Engine: 28 - 35cc

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Think a bit before plumping for the Storch, you may/may not know I have one based on an old plan. Mine is 85" span with 10cc webra glo -weight 10.5 ibs (made mega changes for lightness)

 

Storchs' have very very poor aileron control, and definitely need bags of rudder which is very large to initiate turns. Coupled aileron/rudder is the best option to fly them. Flaps produce major trim changes on the elevators. However they can be great fun and fly incredibly slowly in a head wind. The major drawback is the span of the wings which require takeoff directly into wind else they will tip over very quickly. Ditto on approach, direct into wind, steep approach with some flap on, and a nice burst of power to flare it out. Mine when the engine was new could take off in 3 feet and land in less than that-with some flap on of course. Overall I loved mine, but not the easiest to manage in windy conditions.

 

Hope tips help.

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I have just been delivered a new DLE 30, the only issue being I ordered a 20............ :roll:

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Is that a good thing? I always thought the 20 was a bit borderline on power to weight ;)

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I have just been delivered a new DLE 30, the only issue being I ordered a 20............ :roll:

 

I'm sure there a club member on here, that would buy it off you! That's if you don't need it yourself!

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