Posts: 147
Joined: 12/31/2002 From: Oak View,
CA, USA Status: offline
Doug,
The OS46VXDF motors say nothing in the one page front and back "manual". I e-mailed OS and they say to "4-cycle" the motors for 4-5 tanks. I have a 40 ounce tank and will break one motor in at a time. I figure that 1 1/2 to 2 40 ounce tanks at the 4-cycle will be enough. I do not know what size tank OS is thinking about or uses, but I bet it is not 40 ounces. I will then run two more tanks through them leaning them at the half way point in each tank until they are set. OS says that you can start at two turns out on the high speed needle and that the low speed should be close from the factory but should be 2-3 mm at WOT. I will be using Performance Plus YS 20/20 blend and adding klotz to bring the oil content up to 25% per Bax at OS.
Posts: 147
Joined: 12/31/2002 From: Oak View,
CA, USA Status: offline
Ran both of the motors on Saturday. That Perry pump really gets the fuel moving. I am at 1 turn out on the high speed needle with the Perry pump factory setting, just to get the engine started. I then run up the rpm and richen it to two turns out. Turned 13k WOT at two turns out. It almost seems like it would fly at these rmps. Lots of thrust at 13k. It will definitely get to 20k+. Not a lot of heat coming out of the back either so the motors are staying cool. These are loud suckers though. Registered 108 db in the front and 102 at the back. I had to use ear plugs to stand there and run them in and it was still loud. I am wondering if I should go with a Macs silencer to bring the noise down. Club regs say AMA limit on noise, 98 db I think. Plus, we are on a lake with campgrounds behind the field. That would mean more weight in the nose to balance the plane plus the mufflers would stick out of the nacelles. Anyway, I did get some pictures. Film is being developed as I type this. I should have pix posted by the end of this week.
797 sq. in. wing, wing loading at 25.75 pounds (dry) is 74!! Fueled and ready to fly at 27.75 pounds and 80oz/ft2!!!!!! Eek, almost 4x that of my Goldberg Ultimate. I will have several changes of underwear for this maiden.
Posts: 331
Joined: 7/13/2002 From: Prior Lake,
MN, USA Status: offline
Looking very good, Andrew. Thanks for posting the photos. And thanks for the info in your PM on the pressure tap location through the mounting flanges. I have seen that before, but didn't think of it.
Posts: 147
Joined: 12/31/2002 From: Oak View,
CA, USA Status: offline
Perry pump settings and OS46VRDX settings. Paul, have you had a chance to run in your engines yet? This is my first foray into DF engines, so I am flying blind . I am having a bear of a time. I have a total of 10 minutes on each engine. Today, I couldn't even get them to run for more than a few seconds. I do not want to go too lean and burn them up. I have already eaten two plugs . Any other DF guys out there running this combo, can you help please?!?! Thanks!
Posts: 84
Joined: 6/23/2002 From: Springfield,
IL, USA Status: online
Back when I was doing D/F I & a lot of D/F flyers used jet-a 5 or 10% fuel & a rosse, k&b, or hanger 9 #9 plug in the OS 91,vbm78 & 91 s. If I was going to do D/F again and was going to use the OS46VXDF I would look at using jet-a 15% from wildcat fuels & hanger 9 #9 glo plug. That combination worked in the 90's . jimbo
Posts: 147
Joined: 12/31/2002 From: Oak View,
CA, USA Status: offline
jimbo, thank you. I am actually using Performance Plus YS 20/20 blend. I add another 8 ounces of Klotz to bring the oil content up to 25% per BAX at OS. This drops the nitro content to 18.5-19%, no big deal. The problem I am having, I think, is a mixture problem and setting the pumps up correctly. I will try out the H9 #9s though.
Posts: 97
Joined: 1/15/2002 From: Lawrence, KS, USA Status: offline
The best combination for years has been Wildcat Jet-A Glow Fuel with 5% Nitro & 23% Oil and McCoy MC-9 Glow Plugs. Most of the Ducted Fan engines run better on low Nitro fuel like 5%.
Posts: 331
Joined: 7/13/2002 From: Prior Lake,
MN, USA Status: offline
quote:
ORIGINAL: Gry101
Paul, have you had a chance to run in your engines yet?
Andrew
Hi Andrew,
I don't have my engines yet, so I won't be of too much help. One thing I might suggest, if all else fails, is to go ahead and get the long Mac's tuned pipes. The folks at Jet Hangar Intl. cautioned me about the short pipes when I bought the fans, but I had already had them made. I still hope to use them, but I've heard enough to convince me to get the Mac's and run with those first. After I have a few flights under my belt, I'll put on the short pipes and see if I can duplicate engine performance on the ground. If engine response and RPM's duplicate performance with the long pipes, then I'll switch to the short ones.
The need for properly tuned pipes is really stressed for ducted fans. One of the things that convinced me was an e-mail exchange I had with a student at Texas A&M who was on a team that built a YC-14-like model with twin ducted fans on top of the wings to created added lift. They simply could not get enough power out of the fans (also O.S. '46's w/ Turbax fans and Perry pumps). In desperation, they contacted me after finding my web site. I put all of my advanced intellect to work for them and promply gave them the phone number for Jet Hangar Intl. Even though they got their engine set-up from them, I guess they tried to work things out on their own at first. In any case, Jet Hangar walked them through how to tune those pipes and the rest is history--their plane flew and I'm a hero! (Just kidding.) Anyway, here's a link to their successful flight.
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All Forums >> RC Airplanes >> RC Jets >> RE: My A-10 Warthog Project 
RE: My A-10 Warthog Project - 
. I am having a bear of a time. I have a total of 10 minutes on each engine. Today, I couldn't even get them to run for more than a few seconds. I do not want to go too lean and burn them up. I have already eaten two plugs 
. Any other DF guys out there running this combo, can you help please?!?! Thanks! 