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Building Tips and technical articles. => 1/2 A building. => Topic started by: Target on September 02, 2015, 01:49:51 PM
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Guys-
I bought one of Eric Rules cute little 1/2a Stuka's, and I want to put my old Norvel Big Mig .061 on it. But it is the RC version.
I need the P/N 04-07 venturi to convert it, but the NV engines website has been out of stock for a couple of months now.
I did a search, any place besides Sheldon's hobbies that I should look for one?
Does anyone have a spare they would be willing to sell me?
Thanks!
Chris
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If no one here can provide you with one, Norvel engines are available again as NV engines. Parts are the same and available on line. We had lost several venturis and spinner nuts through the years at Oshkosh, and when NV made the stuff available, Art Johnson was able to get the required parts with no troubles. Might do a search here on the forums about it also. I know my son Sean bought two engines through their web site.
Good luck and have fun,
Dan McEntee
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NV says they ordered them from Russia 45 days ago and there is still no sign of them yet. They think they may be lost in the post.....
I guess I'm SOL for the moment.
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Just read through all the forum posts on the NV site and see that the "out of stock" for the venturi is true for a while now
I think you have several options if you don't find a used venturi to convert the R/C .061
Your plan is for the NV.061 on a Erik Rule 1/2a Stuka so I assume you are fine with running the engine flat out at top RPM like I do with my NV .049 or .061 engines on bladder for Lite Hawk variant combat planes
The stock NVA of the .049 or .061 (both the same) are too coarse a thread to run pressure reliably.
I have several stock Norvel NVA left over from my conversions to Cox Fine thread NVA from Texas Timers.
If you are going to run a hard tank the factory NVA will work fine.
If you plan on low pressure (red cap kitty condom) or high pressure (1/2a sized fuel line bladder) you need the TT Cox NVA ($15.99)
While the Venturi and screen look and work good, most of mine are just plumbed into the case opening
Your BiG Mig .061 RC should have a through bolt and nut holding the carb body to the case. I can send you a complete NVA from a .049 I converted. You would remove your R/C carb and enlarge the through bolt hole to accept the stock NVA across the case intake opening
Or you buy the stock NVA from NV site under the "049 Big Mig parts listing" first page. You have to buy three pieces, the spring clik clip ($2.99), the fuel nipple (should come with the nut) ($6.95) and either a long or short needle valve ($6.95)
I have never learned how to post images on this site and already spent too much time trying to find the correct procedure so: If you need to see both the Norvel Big Mig and AME .061s side by side, and what I am suggesting just send me an email and I will attach the photos
BTW I dislike the stock glow plugs for the NV engines and found the Doug Galbreath Nelson adapter and standard Nelson plugs works fine with the 25%~35% Sig or Riches brew fuel I use in these low cost powerhouse engines
Another hint in case your Big Mig is not broken in... a standard cox glow head reduces the compression, and lets the first few starts be MUCH easier on your frustration level
Note to self...Send Erik an e-mail and order the 1/2A Stuka
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Wow, Fred-
Thanks for all the information. I'm inclined to try to go with a hard tank and a uni-flow setup, if that will work on this little plane. Excuse my ignorance, I'm new to the c/l scene, but having a ball. My OS.40fp that my buddy setup on a uni tank runs so perfectly, never a problem with it. But Eric and others swear by pressure for the 1/2A's, and who am I to argue? My buddy/mentor is an ex combat guy, and he says pressure is fine (but I forgot about the course needle on the Norvel's).
I think some of what I decide will depend on what the front of the plane looks like....
I'll have to bust out the plans and get back to you, but thanks for the offer, and reminder of the needle issue. You've already saved me time, trouble, and money! Thanks so much.
Kind regards,
Chris (who flew his buddies 80mph wing this morning)
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Chris
I just ordered a Eric Rule Stuka 1/2a this morning and pretty sure I will stick either a NV .049 Aero (light short nose) or the standard .049 (longer nose) or the AME .061 or the .061 Big Mig...each is shorter or longer and different weights so it is a matter of what one balances the craft best. In all cases I will be using red cap kitty condoms as I am used to running pressure systems
Hell I might even put on the Picco P-0 (.050 car engine) I got from Galbreath converted to airplane engine
I also have a fair selection for Cox TeeDee and Medallion .049/,051s that may be just right
If, as you desire, the Stuka has adequate room for the hard tank and uniflo; I highly recommend the Venturi and NVA combo* since my method of just the NVA in the case will probably cause you fuel draw issues that are hard to compensate for on these little buggers.
The wide open case intake ( I suggested in the other post)really needs a pressure fuel system. The biggest reason is it (the case bath tub opening) is real close to the crank intake window and there is little or no venturi action. The stock C/L set up places the needle and true venturi 2.5 times further away from the crank window and allows for proper fuel draw and stable needle setting
* Your description of the Big Mig .061 you have might not have the through bolt holding the Venturi in and may be glued in (heat will remove it)....in this case my offer below is not relevant
If yours is indeed fastened with the through bolt I might be convinced to convert my last Big Mig to pressure and would have a spare Venturi NVA assembly to sell or trade away
One other thought sir...If you like the 1/2a stuff and desire good light engines I would suggest buying one or more of the Norvel .049 or .061a currently in stock. $75 for a new NV .061 C/L Big Mig is not outrageous price
I fell in love with these low cost (relatively speaking) for my sport flying ( I am a C/L guy of one in my area). I have 12 of these, some new, some when on sale (Norvel returns) and many e-bay versions. I might be responsible for a shortage of some parts (not the venturi) as I bought a good stock of con rods, gaskets, screws, piston cylinder sets etc in anticipation of what we see now with "out of stock" conditions lasting months and usually never remade for sale.
I got stung with Super Tiger engines this way. A few years back I returned into this hobby and bought several new ST engines from Tower...now I need a few parts, would like to have several NVAs, and other spares to support the engines... EVERYTHING has been back ordered and out of stock for over a year now and none of us have any faith that this will change
I hope I am wrong but I see Norvel heading this way
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I'll attach a picture of my engine later today after my jury duty (uggh).
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Hi Chris,
I may have one!
I didn't think I had a spare Norvel venturi, but just found one in my box of new (Norvel) parts!
Someone may have removed it to install an R/C carb on their engine, as the mount screws are not in the bag, and the needle appears to be the short R/C version.
Looks like new, and has both the intake screen, and base O-ring still in place.
If you still need one let me know.
Bill
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That's awesome, Bill.
I'll give the folks at NV engines a few more days, and if they don't get their shipment, I'd be happy to buy it from you. Thanks so much!
:-)
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OK Chris,
Standing by! ;D
Bill
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Pic of engine.
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So, by posting a pic of the engine, it appears to me that the RC carb has an o-ring seal at the shoulder of the crankcase and the carb is held in with a bolt and nut, as opposed to glued.
All this talk makes me wonder if I don't want a finer needle assembly anyway, so that I can run either high pressure or suction.
Any problem with the super fine needles running on suction? They open enough to work correctly, don't they?
Thanks,
Chris, still waiting for NV engines in regard to the venturi for C/L.
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Chris,
Pressure feed is not necessary for the Big Mig sport tuned engines, but a fine needle thread will work as well on suction feed.
I'm not aware of any fine thread spray bars for the Norvels, unless NV engines offers them.
Ken Cook might know who if anyone offers fine thread needle assemblies for Norvel engines. Ken?
Bill
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Bill your correct that a adapted fine thread or the factory coarse thread both work on suction
The usual problem for those of us who adapt the Cox NVA (128TPI) into the wide open Norvel front case is not enough suction to reliably run off suction/gravity even with good uniflo setup. Many of us do this for a combat set up and bladder
We buy the cox NON TeeDee fine thread NVA from Texas Timers ($10), and sleeve the smaller diameter cox spray bar with 5/32 tube (JB weld or solder) into the bath tub case intake of the Norvel
Ken Cook also made an adapter in the case opening with the hub of a APC broken propeller, tapped the center to screw in a TeeDee Venturi and NVA
http://www.texastimers.com/
Left side under needle valves...on the NVA Page Open the link for pictures and size for the Cox NVAs
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Chris
I keep forgetting to mention that the very easiest way to use your big mig in the stuka is to run the engine as is with the throttle wired wide open
In fact if you have run and broken in that engine already that is exactly what I would do, rather than fuss with the conversion to C/L venturi
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Hi Fred,
I have a few of the Texas Timers needle assemblies bought years ago for possible use in my OK Cub engines. Then I found out the Cubs don't stand up all that well, so never bothered installing one. :(
Also found out that the Cox Medallion spray bars are fine thread, and the TT needles fit perfectly! Unfortunately, the Medallion spray bars are too short for use in the Norvel venturi.
Norvel carbs are much better made than the AP Wasp carbs, and do work fine locked open! I agree that would be a better way to use the Norvels for control line flying.
I wonder if the Norvel R/C carbs could be closed enough to improve fuel draw on AME engines?
Bill
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I wonder if the Norvel R/C carbs could be closed enough to improve fuel draw on AME engines?
Bill
That may not be a problem if you use muffler pressure...assuming you are using a muffler. :)
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I have options now, Gents, because my parts are on the way!
Anyone know how long NV engines takes typically or where they ship from?
And thanks for all the assistance.
H^^
Kind Regards, Chris.
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I believe they ship from California.
If you decide you need to adapt a TT or Cox fine thread NV, here's a How-To I wrote some time back.
http://www.rcgroups.com/forums/showthread.php?t=1863251
Rusty
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Thanks Rusty!
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You're welcome Chris.
If you read that thread near the end, the soft wire-tie I used to secure the fuel line to the crappy barb, is the same one is still on there now, 2 or 3 years later. It worked better than I expected. Once you find your needle setting, it'll never change much, other than a little with temperature and altitude. Always cranks at the same setting, so I never move it. And return it to the same setting after cleaning.
Rusty
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I have been buying from Norvel for the last three years a couple of times a year. Always something that for sure is IN STOCK. Most all the packages got to me under a week and I believe were shipped form a state side address in Calif
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Roger that, Fred.
I'll know soon, it seems I should have first hand experience.
Kind regards,
Chris