RE: Pics of the latest, heavy duty pipe from Fly Eagle Jets...
WOW... he's lucky the model is still in one piece.
Posted on: 5/16/2013 4:28 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11513602

RE: not for the faint hearted
Nice. [:D]
Posted on: 9/17/2012 12:12 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11231336

RE: Fuel line tie wire?
[quote]ORIGINAL: BaldEagel [quote]ORIGINAL: Dr Honda [quote]ORIGINAL: BaldEagel In the latest RCJI Special there is an article on exactly this subject................ also uses a short length of tygon over the fuel tube barb, not tying wire. Mike [/quote] So.... Put the ''Festo'' hose on the barb... and then a ring of tygon over that? I used that trick with silicon hose
Posted on: 9/17/2012 12:05 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11231331

RE: New turnigy/hobbyking powerbox systems
Yep... they put out a vid of it. BUT.... I dont' know if I trust it. They were making a knock-off of the smart switch... and they were failing because of poor quality regulator transistors.
Posted on: 9/17/2012 4:31 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11230847

RE: Fuel line tie wire?
[quote]ORIGINAL: BaldEagel In the latest RCJI Special there is an article on exactly this subject................ also uses a short length of tygon over the fuel tube barb, not tying wire. Mike [/quote] So.... Put the "Festo" hose on the barb... and then a ring of tygon over that? I used that trick with silicon hose... but tygon is hard to stretch.
Posted on: 9/17/2012 4:23 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11230841

RE: YA Skyhawk and Wren 44 Gold Perfect together
[quote]ORIGINAL: Vettster $500 bucks?? Must have been a bunch of EDF'ers thinking they could play with the big boys for the same price..lol[:D] Im not in hurry for one.. Winter will soon be here[;)] [/quote] That's what I was thinking too. I Picked up a boat project for the fam... and I was going to sell my 44 to fund the rebuild. Plus... it was sitting on the shelf for over a year. So I posted it. But, after getting the low offers, and selling a few other things... I decided to finish my T-45 project. At this point... I'm glad I kept it... but I am shocked that it didn't sell. (FYI, it was posted for $1500 with new bearings, and a wren pipe. AND, it only had 2 hrs on the fuel pump, and temp prob) [quote]ORIGINAL: Mark 5 Tony if your T-45 is only 8 LBS ,it will be a rocket with the Wren 44. [/quote] I'm hopping to have it done tomorrow. So... I'll get a weight on it. I'm thinking about turning down the thrust a little. I don't need +1:1 on a little jet. (lol) I think Ron told me that 175K rpm would be 7#. I guess I took it a little off subject. Sorry. I'll shut-up now. [:D]
Posted on: 9/16/2012 7:22 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11230537

RE: YA Skyhawk and Wren 44 Gold Perfect together
[quote]ORIGINAL: Mark 5 Hi Tony, the Skyhawk weighs 12 and 3/4 LBS without fuel. I dont know how guys are getting them under 11 LBS. This combo flies very scale like at a little above 1/2 throttle and the light wing loding seems to help when landing. Mark [/quote] Thanks for the info. I was worried about the 44 gold, and general grass flying. So... with fuel... you are at about 14 Lbs I guess. I'm projecting my T-45 at only being at 8~9 Lbs with fuel. I also left the retracts out, and put on 3" tires. (lol) I'l be the only guy with a "Tundra" T-45. [quote]ORIGINAL: Vettster [size=4][b]If anyone is selling a Wren 44 Gold.. I am interested[/b][/size] [/quote] I had my 44 for sale for a few months. People were only offering $500... so I pulled it. They don't come up too often on the used, but hang in there... you'll find one.
Posted on: 9/16/2012 3:25 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11230288

RE: Fuel line tie wire?
I also use stainless safety wire. I will update with the size later. ********Edit***** My spool is 0.030". It works, but it's a little thick. I'd recommend something thinner. 0.020" would be better.
Posted on: 9/16/2012 11:34 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11229815

RE: YA Skyhawk and Wren 44 Gold Perfect together
What's the ready to fly weight? I'm just finishing up a T-45... and I'm planing on flying it from grass. One thing... I know they are a little pricey... but if you change to the Wren pipe... they claim a 5% thrust increase.
Posted on: 9/16/2012 4:14 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11229810

RE: How to Correct Measured Thrust for Density Altitude?
[quote]ORIGINAL: rctech2k7 I agree, it’s really complicated to determine parameters of an engine, because it takes time and some guts to analyze thermodynamics process. To be practical I just used value on the output side of an engine and get comparison between the test result. It also eliminate other variable including constant... BTW, I've got mistake here, I should consider intake airflow because in reality air accelerates around the turbine and becomes free stream. So even the engine is on a test stand it has airspeed when it's running. Here's the formula for Thrust from http://www.grc.nasa.gov/WWW/k-12/airplane/turbth.html so we can solve it again. [image]http://www.grc.nasa.gov/WWW/k-12/airplane/Images/turbth.gif[/image] BTW, rctech2k7 is a short for RCTech2007. Rctech was taken when I signed up but since I started in RC on year 2007 I used 2k7, where ''k'' is derived from a technical prefix kilo. Good to know that we have someone here with degree of Physics, very interesting... You might help us about adiabatic expansion. BTW, my background is electrical engineering. What I've also learned makes me to appreciate the network and technical part of this hobby specially the high energy performance of our jets, flight control system, etc... Let's go back to the topic, I tried to approximate using this formula and it's almost the same although the fuel consumption might change it slightly when running at low air density where mass flow to the exhaust will increase... [/quote] I agree with Tim on this. The above pic is great example of "eye candy." Sure... the formula may be sound... but there is no way to measure any of that without expensive, high-end test equipment. Let's just look at the thrust end. How are we supposed to measure the velocity? It's very hot, so we would burn ourselves in a "Garage" situation. Also... most of our engines are making thrust in the supersonic range. (+1000 MPH) So... I don't know about you... but my little kestrel wind gauge wont' go that high. (lol) To try to calculate things is just too hard. If you guys want a generalized equation... then build a test rig, and test as many engines as you can at sea level.... then re-test them at 2000 MSL, and 4000 MSL. Also... we will need the data on LL and HH conditions at those altitudes. At that point, we can take the data, and build a equation that fits the curve.
Posted on: 9/15/2012 5:40 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11229140

RE: Hamburg Jet Jam roll call
I'm planning on coming out this year. I want to see Todds new mobile rig.
Posted on: 9/15/2012 5:00 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11229119

RE: Hobbyking BD5 for Jetcat P20
DrDoom: I was ready to say... "That BD-5 is HUGE!!!!" But then I realized that's a Falcon 25. (lol)
Posted on: 9/14/2012 4:50 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11228134

RE: Hobbyking BD5 for Jetcat P20
I was looking at that the other day. I was thinking Wren 44... but I'm sure it will fly on a P20.
Posted on: 9/13/2012 2:13 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11227569

RE: Falcon 120 Help!
Those are good points. I think the later kits did have a short tube. (Covering reminded me of this) the wings popping from pressure is a real issue. There were a few that crashed because the wings came apart in fight... but they all seemed like they didn't install the landing gear buckets. (so the wing was open on the bottom) Make sure you cover any open, external wing holes!!
Posted on: 9/13/2012 9:30 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11227303

RE: How to Correct Measured Thrust for Density Altitude?
[quote]ORIGINAL: ww2birds Remember on Gilligan's island when Gilligan would hear and argument and agree with both sides? I think that Dr. Honda is saying that it's hard to compute thrust for a specific turbine design just from basic parameters like inlet diameter, rpm, etc. That seems reasonable, they are complex beasts and there is so much art in the combustion chamber and NGV to name
Posted on: 9/13/2012 6:08 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11227115

RE: Flaps
I gave up on Hitech after I lost a 3rd heli from a failed servo. But regardless.... the above advice is good. Get a meter, and check the draw. You don't want a bind. A current draw could cause a brown-out (reset) on 2.4.
Posted on: 9/13/2012 5:54 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11227101

RE: Falcon 120 Help!
I'm all for doing mods... but there is no reason to put a carbon tube in this model. On the "Falcon 120" thread... we had this debate for a while, and NO ONE actually broke, or bent an aluminum tube without some other source of damage. (like a very hard landing) and in those cases... there was other damage that would would have keep it from flying. As above... the Heli booms were too thin. So... that's not a viable option. And... as XairFlyer said.... they float, and weight is almost not an issue. My falcon is 22 Lbs on take off... and flys great. Trying to save a few oz isn't worth the $$$. Just an FYI... in my Falcon, I added a balsa block to the inside... and it supports the root at the fuse. So... a lot of the weight/pressure is supported using the wing bolts.
Posted on: 9/13/2012 5:04 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11227049

RE: How to Correct Measured Thrust for Density Altitude?
[quote]ORIGINAL: highhorse Dr Honda: I hope you are wrong. Otherwise, how can the folks at RCJI publish comparisons? Surely the weather changes would invalidate their data... Tim: Thanks, but I'm NOT looking for definitions of air density, please re-read the OP ;-) I'm looking for quantitative correlations between density and thrust for a given engine. [/quote] Well... I'm sure
Posted on: 9/12/2012 4:35 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11225910

RE: CO2 extinguishers
[quote]ORIGINAL: Captainbob Guys, CO2 is probably the least desirable types for our purposes. Shop around for Halon - much more effective. [/quote] I have a Halon... and it's expensive to refill. So... I went out and got a CO2. Anyway... to the OP... I'm not sure why they are expensive... but they are. I picked up both of my extinguisher from ebay. I think I paid $65 for my Halon, and $40 (shipped) for my 20# CO2. The Halon was new... and the CO2 was used... but certified, and full on delivery.
Posted on: 9/11/2012 7:14 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11225643

RE: How to Correct Measured Thrust for Density Altitude?
On a "Pure Jet" engine... there isn't a general formula for thrust and pressure/altitude density. On a prop, or fan jet... you can calculate how the prop/fan pulls on the available air. In a pure jet... you loose power, and in turn, lose thrust. Since none of these engines have the same efficiency... and since our engines make thrust exponentially... the actual thrust lost equation would be specific to the engine you are working with.
Posted on: 9/11/2012 7:10 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11225639

RE: Dreamworks Mobile Products - Officially Launched!
Hey Todd, Just a thought... You may want to get George to join this board. That way... if there is a special request, he can make sure to have it in stock before he rolls out. Also... I'm sure that majority of his customers will be here too. (for feed back, and better customer service)
Posted on: 9/11/2012 5:07 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11224974

RE: HobbyTopgun MIG-15 with Kolibri T25 turbine! *video*
Very nice. If the Kolibri turbines were so dang expensive in the USA... I'd get one. (it's hard to justify $3200 for a foamy) BUT... I know the guy from Ausi Jets hand massages the JJJ engine, and gets them to run right for $1600. (hummmmmmm)
Posted on: 9/11/2012 7:55 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11224985

RE: Dreamworks Mobile Products - Officially Launched!
I guess I'll have to come out to Hamburg to say hi. Todd... you going to be there... or just George?
Posted on: 9/10/2012 12:57 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11224017

RE: NEW - ELECTRO-BRAKE
Looks good. Glad to see them come to market.
Posted on: 9/10/2012 8:00 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11223672

RE: Model Jet Engine In A Glass Enclosure
Old vid... but still cool. (looks like it's an advertisement now)
Posted on: 9/10/2012 7:48 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11223660

RE: 2012 Fall Jet Fun Fly – Are you ready for OC-Turbo Fest?
Spring this year was a bit windy... but a nice day. I'll see if I can be available for this one.
Posted on: 9/8/2012 9:13 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11221774

RE: Keep you electric guys happy
Interesting. Not only would they save fuel on the turbines... they wouldn't need the tug's either.
Posted on: 9/7/2012 5:56 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11221229

RE: Turbine Heli Qualification
Thanks. I'll try to clear my scheduled, and get out for it.
Posted on: 9/7/2012 5:51 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11221222

RE: 100lbs thurst micro jet Bladon Micro Jets
Yep... it was my understanding that the engine doesn't actually run. Put it sure is pretty.
Posted on: 9/7/2012 2:39 PM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11221046

RE: Turbine Heli Qualification
Mark... you have someone at the ARCS wanting a rotary turbine waver?? I'd like to come out and see those flights. Hey... a little off topic... but when is your fun fly at?
Posted on: 9/7/2012 5:54 AM by Author "Dr Honda" in the forum "RC Jets"
http://www.rcuniverse.com/forum/fb.asp?m=11220538