RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
what happens to the plane sound when it moves towards you, and then it moves away from you? Does the sount pitch (=rpm) stay the same? Wind has the same effect.
Posted on: 11/18/2009 4:45 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9263408

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
[quote]ORIGINAL: tripower222 not sure i understand how wind comes into play in the accuracy of the rpm reading [/quote] The soundwaves upwind are denser than the soundwaves downwind, due to Doppler effect.
Posted on: 11/18/2009 12:44 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9262855

RE: Are Hall Sensors Interchangeable between brands?
The Vlach ignition uses a bipolar type in order to detect both south and north orientaded magnets. Since Vlach is OOB, the only way to go about it is dismantle the sensor and order the same type number hall sensor (electronic's hobby shop)
Posted on: 11/18/2009 11:01 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9262645

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
if there's a 20 mph wind blowing, you'll be off about 3% [;)]
Posted on: 11/18/2009 10:54 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9262633

RE: Help RCEXEL ignition
Nice picture Jody
Posted on: 11/18/2009 8:38 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9262398

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
[quote]ORIGINAL: RTK Now you are showing your age Pe:) [/quote] No need to hide the fact that I'm a warchild. I did my first (of many) engineering exam in 1961. I still find my sliderule a nice tool when I need quick fixed ratio references and three-set calculations. BTW, For those interested, NACA did a lot of good static prop research in the 1920ies. It makes nice reading.
Posted on: 11/18/2009 7:59 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9262336

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
That's a good idea. I welcome data, even if I can't use them all. Be sure to include plane fuselage shape, because the plane drag reduces the fish scale reading.
Posted on: 11/18/2009 7:50 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9262321

RE: glow to steam conversion?
A teflon valve in the head, with small stem toward the piston crown for piston operation would be much less complex.
Posted on: 11/18/2009 7:44 AM by Author "pe reivers" in the forum "Engine Conversions"
http://www.rcuniverse.com/forum/fb.asp?m=9262311

RE: Are Hall Sensors Interchangeable between brands?
That was not his question. He asks what can be done to test his Hall sensor, and eventual replacement (costs only a few bucks), so it can be spliced into the original cirquit.
Posted on: 11/17/2009 6:21 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9260998

RE: Header and Teflon tape question
Your header will see local hotspots in excess of 400F. The MT header is made of seamless corrugated tubing, unlike many rolled corrugations which are not seamless. The rolled headers should be sealed by winding a twisted strand into the corrugations, and then tightly wind about three overlapping layers over the header. The non-rolled corrugated tubing, like straight bent tubing will benefit from a teflon wrapping in that it keeps the header inside hotter, and the engine cowl environment cooler. It also provides for better smoke if you have a smoke connection.
Posted on: 11/17/2009 6:15 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9260976

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
I am happy with less than 5% inaccuracy. This was the accuracy limit imposed on us in engineering exams when using a slide rule instead of electronic calculators.
Posted on: 11/17/2009 6:03 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9260942

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
I started out with basic prop calculations, and through the years compared props I had good data for, at the same time tweaking the constants to adapt the outcome to real world results. If you have a known engine that you can mount the unknown prop on, you can adapt the prop factor until results match measurements. Calculations will improve if you can test a handful of the same size props. An electric motor is a great tool, as most parameters are known.
Posted on: 11/17/2009 11:10 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9260081

RE: glow to steam conversion?
http://www.animatedengines.com/co2.shtml
Posted on: 11/17/2009 8:35 AM by Author "pe reivers" in the forum "Engine Conversions"
http://www.rcuniverse.com/forum/fb.asp?m=9259807

RE: have engine ST 3250, Now what airplane to choose??
This engine is not the lightest around, but once you get the carb dialed in it is a very solid performer for IMAC style ot heavy duty towing planes. Read my web pages for midrange carb tuning and using a walbro carb fuel pump/pressure regulator. Bob Pastorello also knows a thing or two about getting the most out of a ST carb. The best I ever seen if you follow the instructions on fuel flow and midrange modifications. BTW, DO run 10% oil 5% nitro and an OS-F plug, or be sorry.
Posted on: 11/16/2009 6:08 PM by Author "pe reivers" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9258499

RE: glow to steam conversion?
Oh dear! Low rpm small displacement engines on steam never quite made it beyond the showbench. For simplicity, you could use the CO2 engine principle with a piston operated steam admittance valve. There would be uniflow, and least pre-condensation/after-evaporation problems. Apart from that, it would only require a new head and plumbing, with open crankcase and occasional drop of oil to the rod/shaft.
Posted on: 11/16/2009 6:00 PM by Author "pe reivers" in the forum "Engine Conversions"
http://www.rcuniverse.com/forum/fb.asp?m=9258484

RE: what is the simplest/safest/most reliable radio system for a giant?
Hey! this is a whole can of different questions from your first posting.
Posted on: 11/16/2009 5:53 PM by Author "pe reivers" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9258472

RE: Is there a formula or chart for prop diam/pitch an rpm = HP?
or just http://www.mvvs.nl/prop-power-calculator.xls
Posted on: 11/16/2009 3:53 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9258192

RE: what is the simplest/safest/most reliable radio system for a giant?
There are two ways to go about it. The KISS principle, which most 9-channel radios will support, or the BEST principle, where you need the best programmable digital servo's, NO Y-cables, and a power box that will supply just the power that those servo's need. The price difference between those two systems is, depending on the requiremets slate, HUGE! So In order to answer your original question, it is nice to know some more facts about what you realy want.
Posted on: 11/16/2009 2:53 PM by Author "pe reivers" in the forum "Giant Scale Aircraft - 3D & Aerobatic"
http://www.rcuniverse.com/forum/fb.asp?m=9258072

RE: MVVS 1.6 IFS erratic operation
You have a lot of issues, and narrowed them down. One major issue seems to be the carb going lean indeed, due to a malfunctioning high speed cirquit? That explains the early advance running better with small spark plug gap (which retards combustion onset). Beg-steal-borrow a good carb, or bring the carb to your nearest garden appliance shop for a checkup. (if they have good craftsmen there!). Be sure to tell them your findings and history. You also can order a new carb, and save you a lot of hassle, budget permitting. Your problem seems to need a major carb overhaul that most are not willing to do (included me, I just do not have all the required tools).
Posted on: 11/16/2009 2:45 PM by Author "pe reivers" in the forum "MVVS Support"
http://www.rcuniverse.com/forum/fb.asp?m=9258051

RE: ICU-P ignition Ver.2 (custumized version?)
All ICU ignitions with M14 plug boot work with the magnets at 180 degrees. I have to ask MVVS if 120 degree magnets will be a long term problem. The ignition works OK with them, or so it seems.
Posted on: 11/2/2009 4:19 PM by Author "pe reivers" in the forum "MVVS Support"
http://www.rcuniverse.com/forum/fb.asp?m=9223029

RE: noob to gas - Oil Question
Please let us know how it works out?
Posted on: 10/31/2009 6:52 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9218370

RE: ICU-P ignition Ver.2 (custumized version?)
MVVS supplies conversion units, so old Vlach (M14) systems can be changed to the new ICU ignitions. According to MVVS, the systems with M14 plug boot are made to work with the magnets at 180 degrees apart, so no change of prop drive is required.
Posted on: 10/31/2009 6:38 PM by Author "pe reivers" in the forum "MVVS Support"
http://www.rcuniverse.com/forum/fb.asp?m=9218336

RE: Fox sells DLE?
no more DLE on the Fox page.
Posted on: 10/30/2009 3:09 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9215473

RE: 55 cc engine
Nice project. I'm with Aussiesteve on this one. Don't fall into the what-if trap.
Posted on: 10/30/2009 7:58 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9214572

RE: noob to gas - Oil Question
And check fuel used. Fuel changes also may require re-tuning. Be sure to use quality fuel, and not the cheapest stuff you can get. Premium will be fine.
Posted on: 10/30/2009 7:41 AM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9214553

RE: Problem problem problem
prop is too large for a new LA engine. A 10x6 is plenty prop for any .40, especialy when running in.
Posted on: 10/29/2009 6:37 PM by Author "pe reivers" in the forum "Glow Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9213236

RE: Walbro, tillotson....universal problem?
Even most engine manufacturers shy away from the cost to get a carb just as it should be for their engines. Instead they pick one from the many many available, and hope it will work out ok. In the process, they even look at the competition, and use the carb already in use hoping it will be the right one for their own use.
Posted on: 10/29/2009 6:34 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9213227

RE: Evolution 26GX - choke operation
No. A manual operated choke works just as well, though a servo operated choke can be easier to operate in small steps.
Posted on: 10/29/2009 2:12 PM by Author "pe reivers" in the forum "MVVS Support"
http://www.rcuniverse.com/forum/fb.asp?m=9212499

RE: Walbro, tillotson....universal problem?
The main problem with membrane carbs on single cylinder engines (or opposed twins) is that the carb membrane admits a little bit of fuel EACH stroke. The main needle opens and closes, bounces on the seat, and the fuel admission rithm may get out of tune with the engine rpm. This can only be solved with a large plenum chamber, which however opens up a new can of worms. Another problem to address is the idle transition mixture control. Walbro type carbs (walbro, tillotson, bing, dell'orto etc) have a strange way of brake air mixing into the fuel flow. At one time the second or third idle jet acts as brake air jet, the other time it acts as idle jet. This makes tuning a membrane carb very difficult. In float carbs there were well defined and well separated items like slide chamfer, slide needle, main jet, air jet and float height to play with. Still quite a few variables, but a mechanic savvy to his engine would have the tools in his box to tune the carb for the day, morning or evening. If I play with the seemingly simpler walbro, it often gives me fits, because one change influences almost the whole adjustment range. No wonder there are so many Walbro numbers available, without any system in the numbering. Some folks at Walbro seem to know what they are doing, but the best they can do is make a new setup for a new engine. Or so it seems. Edit: Grammar.
Posted on: 10/29/2009 1:47 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9212385

RE: noob to gas - Oil Question
[quote]ORIGINAL: ndb8fxe Just bought a plane with a Brillelli 46 on it. The seller ran it and flew it before purchase and all seemed well. I flew it that day as well. He said he was running a 50:1 ratio of synthetic. So I went and flew the plane today with my own different brand synthetic with a 50:1 ratio and the engine didn't idle very will and didn't seem to make as much power either. Will a different brand of oil cause a engine to run differently? Seemed to me like it needed needle adjustments, but I didn't mess with it any more. I did get a few good flights in, it just didn't seem the engine was running right. Thanks in advance. [/quote] Please DO mess with the needles, PLEASE?
Posted on: 10/28/2009 7:05 PM by Author "pe reivers" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9210382