My Engine

[Dirtydog]

treaze : Dido on the razor knife. I used arazor knife for a model airplane building kit that I had. pointed blade works great to start it in place.

Now I will say that when I was in the army and had to replace one of the instruments on the helicopter I was asigned to take care of as the crew cheif I would take paint with a fine brush as you spoke of doing. to mark mine.....

 

[treaze]

Fortified with encouragement, I managed to overcome shaking and cramping hands, and mark my quad with green arcs and redlines. That's all I'm going to do with that. Something this little task highlighted for me is that with an instrument this small, the green bands are only approx 3/16", which is almost ridiculous. I might as well be using idiot lights instead. Oh, well. Next up is marking the throttle and ign sw when I get the label printer from Amazon and the black vinyl tape with clear background I'll need.

 

[Redbaron]

hey treaze, you will be surprised at how little you stare at the egt/cht guages while airborne. I flew with the egt/cht guages at first then got rid of them "cht never over 300f" and I always checked the spark plug color! CHT will rise quite fast if your cooling fan belt breaks tho. just my 2 cent imo.

Fortified with encouragement, I managed to overcome shaking and cramping hands, and mark my quad with green arcs and redlines. That's all I'm going to do with that. Something this little task highlighted for me is that with an instrument this small, the green bands are only approx 3/16", which is almost ridiculous. I might as well be using idiot lights instead. Oh, well. Next up is marking the throttle and ign sw when I get the label printer from Amazon and the black vinyl tape with clear background I'll need.

 

[Alan_Cheatham]

hey treaze, you will be surprised at how little you stare at the egt/cht guages while airborne. I flew with the egt/cht guages at first then got rid of them.........................

Gauges really become important not when everything is going right but when something is going wrong.

I have original video of a gyro OEM demonstrating his newest creation but unfortunately his EGT was not working prior to flight. "Oh well, what can happen in one flight" he thought. Great looking crank and bank video with the engine sounding super, that was until it seized and down he went in a low altitude vertical landing that broke the ships tail tube and tore up the blades. Luckily no injuries.

I myself prefer digital instruments with alarms as the alarms can be wired into the intercom for audible alerts.

.

 

[Redbaron]

hey alan, do you think he was looking at the guages when the engine seized? sorry about your friend. digital alarms wired into the intercom sounds like a really cool idea :yo: was it a hirth?

Gauges really become important not when everything is going right but when something is going wrong.

I have original video of a gyro OEM demonstrating his newest creation but unfortunately his EGT was not working prior to flight. "Oh well, what can happen in one flight" he thought. Great looking crank and bank video with the engine sounding super, that was until it seized and down he went in a low altitude vertical landing that broke the ships tail tube and tore up the blades. Luckily no injuries.

I myself prefer digital instruments with alarms as the alarms can be wired into the intercom for audible alerts.

.

 

[Alan_Cheatham]

hey alan, do you think he was looking at the guages when the engine seized?

I doubt he was staring at the gauges while cranking and banking but had the EGT been working that day he would have realized soon after takeoff his mixture wasn't right for the density altitude and needed adjustment. The thing is the engine (Rotax 503) sounded like it was running perfect right up till seizure, which took two seconds from full throttle to stopped. A working gauge would have prevented this mishap.

One other unusual "tidbit" came to light from the incident.
The landing, which was basically vertical, was hard enough for the pilots weight to compress the seat tank somewhat and pop the rubber fuel stopper out of the bottom of the tank creating a fuel leak. Not a cool thing to have happen.

.

 

[StanFoster]

Red- With your analogy, I may as well chuck my rotor tach, its always in the green just under 620. My EGT never has given me any high temp indication, chuck that. My voltmeter says my batteries are always topped off, chuck that and save a few more ounces. My oil pressure and temps for my main transmission and turbine have never showed low oil pressure or temps, can get rid of those too! On the other hand, maybe I just havent had any thing out of nominal yet making my gauges not earn their pay. However they are very well indeed earning their valuable real estate in my instrument panel showing me all things are fine, and are their to yell at me when things arent working right. Stan

 

[Redbaron]

I would definatelly want all those things in a helicopter stan. I don't have alot of room for guages. My analog tach is mounted beside my throttle at the moment in a 2 inch hole. I had a westach dual egt/cht guage mounted there but it died for some reason. I do have a single cht guage in my parts box I could replace with the tach, then I could just install a tiny tach.

Has anyone else had seizure problems with the rotax 447 or 503 while in the air? Does the egt guage respond in time to get back on the ground?

Red- With your analogy, I may as well chuck my rotor tach, its always in the green just under 620. My EGT never has given me any high temp indication, chuck that. My voltmeter says my batteries are always topped off, chuck that and save a few more ounces. My oil pressure and temps for my main transmission and turbine have never showed low oil pressure or temps, can get rid of those too! On the other hand, maybe I just havent had any thing out of nominal yet making my gauges not earn their pay. However they are very well indeed earning their valuable real estate in my instrument panel showing me all things are fine, and are their to yell at me when things arent working right. Stan

 

[treaze]

Seated in my gyro with the instruments installed and decaled, I suddenly realized I wouldn't need my glasses to read the instruments--yay! The decals do the trick. I was starting to hook up the pigtail that Westach provides, to test the senders, and discovered that one of the connectors is missing. @#$%&! It looks like it was never soldered on. So I have an email in to Westach.

This is slightly off topic, since it's not engine related, but for an ASI, I was intending to get a Hall. The large unit, calibrated to 80mph, right? And what about mounting it to the control stick--has anybody done that? Successfully, that is.

 

[Redbaron]

sorry for messing up your thread, treaze. take my opinions with very little salt!

Seated in my gyro with the instruments installed and decaled, I suddenly realized I wouldn't need my glasses to read the instruments--yay! The decals do the trick. I was starting to hook up the pigtail that Westach provides, to test the senders, and discovered that one of the connectors is missing. @#$%&! It looks like it was never soldered on. So I have an email in to Westach.

This is slightly off topic, since it's not engine related, but for an ASI, I was intending to get a Hall. The large unit, calibrated to 80mph, right? And what about mounting it to the control stick--has anybody done that? Successfully, that is.

 

[treaze]

While I'm waiting for my connector to wend its way to me from Westach, a couple of comments made on this thread recently reminded me that I have unfinished business to attend to:

(1) Fuel filters--Rotax specifies in their Instl Manual (p.15-2) that the inline filter should be 0.15mm mesh and an in-tank filter should be 0.3mm mesh. I already got filters installed, but the trouble is, I can't find a single filter in any catalog I have where they state what size mesh. Does anybody have a source for the required filters that documents mesh size that'll meet specs? I've read somewhere that too fine of a mesh can result in engine stoppage from either debris or scum.

(2) Fuel tank vent--I drilled out the vent ftg on my Starbee tank just enough to accommodate swaging in a short length of pulse line and then stuck a brass fuel filter with a check valve into the end of that. But it has been bothering me that a hit on the tank might pop that assy out of there, resulting in a fuel spill. So I'm going to work on securing that in some way.

 

[Alan_Cheatham]

Treaz,

Too course a mesh (larger openings) can allow debris to get to the carbs while too fine a mesh (smaller openings) can restrict sufficient fuel flow.

One suggestion I have is to do a gravity flow test through the filters, you should be able to gravity flow at least or more fuel than what the engine will drink at full throttle. Don't rely on the fuel pump to "suck" the proper quantity of fuel through the filters.

I'm not sure what you have there in the way of a check valve on the fuel tank vent line but you want the tank to vent in both directions at all times. Some tanks can be equipped with a valve that closes if the aircraft rolls over, this may be of some value, but you don't want to put in a valve that lets vent air into the tank and not out, the tank needs to "breathe" to equalize changes in atmospheric pressure.

Pardon me if I've misinterpreted your post.

.

 

[treaze]

Alan - Hey, thanks for the good save! Obviously, I've got to remove that filter/check valve at the tank vent, and figure out what else to do there. But I'm still looking for a tank and inline filter with specs good for the Rotax. I hate to just guess.

 

[treaze]

I got my Dymo Rhinopro 1000 labeler, and it seems to work pretty well. I just ordered some label tape with a clear background, though, so here's another week's delay at least.

Re filters, lacking any specs on available products (welcome to the wonderful world of homebuilt ultralights!), I think what I'm going to do is use the only brass tank filter that's advertised by just about everybody for use as a tank filter, and order a Rotax p/n 414-3636 inline filter from somebody (even though it has a paper element).

Re the use of a check valve at the tank vent, Alan, I've had second thoughts. I think it may be ok, after all. I've been playing with it all day, sucking and puffing through it at different rates, checking out the check-valve action. When oriented vertically, it seems to me that under conditions of normal fuel usage, and with any climb to altitude, the check valve does not activate with that typical slow pressure change--ambient air is free to bypass the check valve ball and filter in either direction. But with an upset or sudden pressure increase within the tank, caused, for instance, by a crash impact, the check valve would activate.

 

[Alan_Cheatham]

Re the use of a check valve at the tank vent, Alan, I've had second thoughts. I think it may be ok, after all.......

Treaze, what are you trying to achieve with the vent check valve, what is your thinking on installing one?

But with an upset or sudden pressure increase within the tank, caused, for instance, by a crash impact, the check valve would activate.

With the tank vent closed the pressure rise in the tank would be higher than if the vent were open and so make it more likely to blow the rubber stoppers out that typically mount the fuel pick up line. A check valve would make the situation worse so my advise is no check valve.

.

 

[Dirtydog]

treaze : Great to see you at it again....eace:
I used the one on the bottom, mine came with the plastic connector. I had a problem this past fly'in with one of the ends leaking.

 

[treaze]

Thanks, Dawg.

Alan, I don't have any rubber ftgs to blow out. The check valve integral with the vent screen is to stop the outflow of fuel in the event of an upset. The check valve does not activate with slower flows associated with tank pressure changes expected with fuel usage and altitude changes. So what's not to like?

 

[treaze]

I finally got my shoddily constructed Westach pigtail assembled (missing connector, half the crimps uncrimped, shrink tubing unshrunk), and I've connected up the CHT and EGT senders to my Westach quad instrument. I can get a soldering iron applied to the CHT thermocouple senders to register on the meters. But using the same technique, I can't get the EGT's to work. Any ideas? Is there a method for doing this that I don't know about? I don't have an engine yet, but I wanted to test everything out as much as possible beforehand.

 

[Alan_Cheatham]

Use a torch to test the EGTs as it's unlikely a soldering iron will be hot enough to move the needle off the bottom peg. I use a small Butane torch.
.

 

[treaze]

Alan - You're right, thanks. A torch works. Something else: Hook them up one way, and they don't work. Swap the leads, and they work. Sheesh. So now my quad works.

Ok now, the other almost engine-related mini-project I'm working on is calibrating the fuel tank. I ordered some flat black Krylon Fusion spray paint that hopefully will work on Starbee's polyethelene plastic to mark the gallon levels. And I want to use a convex mirror like Ralph had. Does anybody have a good source for a mirror that will clamp onto 1" Dia tubing? What I've been finding so far are mirrors that won't clamp onto tubing that big in dia, and mirrors that are huge. I might end up making my own mirror assembly, using a clamp, a backing, and a stick-on mirror.