KR> World Tour
Congratualtions, Colin. Well done. You are following a trail blazed by Charles Lindbergh, not only in the general flight route, but in goodwill. I wish you well, as, I'm sure that everyone on the KR list does, too. Dan Branstrom
KR> On slime and nitrogen in tires.
A note for those using slime in their tires. It is fine on tires that use tubes, but if you really want to piss off your local tire dealer, use it on tubeless tires. It makes a real mess on the wheel and difficult to work on. The reasons for using nitrogen to fill tires is that it doesn't migrate through rubber as fast as air, it expands and contracts less than air does when the tire temperature changes, and it contains less water. http://www.popularmechanics.com/cars/how-to/a3894/4302788/
KR> Parachutes
Some considerations: First, I'm not a big fan of Cirrus' system on its planes. Why? First, let me point out that the descent rate on a Cirrus under a canopy is more than a (What is now called) Cessna TTx in a glide. It is for good reason that the Cirrus has seats that are designed to cushion a high vertical G load in a crash or parachute deployment. A KR has no such cushion or crush area under the pilot. Generally, it is the vertical component of a crash that is a high factor in survivability when crashing on a relatively smooth surface. Ya go straight in, you're gonna die. If you don't have a crush area under you, you may end up a lot shorter. Next, the Cirrus has a definite deployment envelope. There have been several crashes, if I recall correctly, where the airplane was found in one spot and the chute in another because, obviously, the chute was deployed at high speed and simply ripped away from the fuselage. There have also been crashes where someone deployed the chute too close to the ground, perhaps to stop a pattern altitude stall/spin event. I think it's good that Cirrus has apparently started training for deployment of the chute, because the fatality rate for Cirrus was actually higher than for comparable aircraft. Perhaps it was a psychological over-dependence on the chute or a misunderstanding of the deployment envelope. The Cirrus is a slick airplane, and it is easy to exceed the deployment speed with the nose pointed down. Another thing to consider when wearing a chute is the ability to get out of the plane. Will your canopy open enough to get out? It is for good reason that aerobatic planes usually have a way of ridding the canopy so that the person can leave the plane. In the service, we didn't have ejection seats, (that tells you how long ago it was) but we did have the ability to blow the canopy open. I knew one guy that had a midair in the pattern (1200' agl, if I recall) and he made it out successfully, but he acted instantly. The other pilot didn't, and died. Have you practiced getting out of your plane as quickly as possible? It's easy to get tangled in seat belts and headset wires, and, in a KR, you're sitting with your legs under the instrument panel. Even if you roll the plane upside down to fall out, what can hang you up? Remember that we only hear stories from survivors. The people who didn't make it out, or died can't tell us how wonderful their chute was. Dan Branstrom --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
KR> Belly board
Herbert wrote, "..my bellyboard turns down to about 80 deg. and after talking to some aerodynamicists and some practical trials I decided to let the board without holes. The tests I made are very simple.I took a foamsheet ( 1 meter x 1 meter x 5 mm) ,fixed 5 strings to the edges and the center with a weight (about 100 grams ) and used my "parachute" as testdummy. I dropped the dummy from my ten meter high rooftop (5 trials without holes and 5 trials with holes) and compared the times I measured. It was easy to recognice that the board without holes always gone down slower ! There was a big difference how they sank down.The board without holes tumbled much more than the Board with the holes (due to the holes,of course) Happy New Year again,Herbert, German Kr Bilder Von meinem" The board without holes fell slower in your test. The problem is that at the speeds a belly brake is deployed, the holes in the belly board may generate vortices or turbulence, and hence, parasitic drag, that is more of a factor at the 100+ kph (62 mph+) that a belly brake is deployed. Note that the people who have flown both with and without holes report more drag with the holes. I would also think that there might be different interactions between the belly board and fuselage or tail when there are holes in it that contribute to the difference. That's why flight testing is so important, with the real world conditions.
KR> Belly board
I always wondered about the holes in a belly board. The T-28s I flew had them on the belly mounted speed brake that was flush with the fuselage when retracted. I could only imagine that the holes gave it greater drag because of conflicting vortices generated by the holes. At the KR gathering, I noticed that our British friend had holes in his belly board. I've noticed that the speed brakes on jets don't have the holes. Even retracted, they cause some disruption of the airflow because the surface is not smooth because of the holes. At the higher speeds of jets, since parasitic drag goes up as the square of the speed, holes like that could significantly add drag. A T-28 usually cruised at about 200mph. That's just about the approach speed of jets. Of course, as home builders, by using foam and fiberglass, bumps made on the belly could fill the holes retracted, but at the speeds of a KR, the drag caused by the retracted speed brake may not be significant. Dan Branstrom
KR> Lithium Ion Batteries
Nerobro wrote: BeLite is using LiPo batteries in their ultralights. Greg was kind enough to send me a copy of his posting, but I don't see posts on KRnet until the next day. Here was my reply to him: There are several factors here. First, [on the Belite], is the lithium battery a part of an electrical system that includes a generator/alternator for charging? Maybe I missed it, but in a brief look at the Belite website, I didn't see any mention of it. The electronic instruments that they sell are very low drain, and wouldn't require much of a battery, so simply having a battery that is charged on the ground would make sense. Does Belite provide anything but the barest information on the battery, or how to charge it? I thought of Belite as an ultralight, part 103 craft, but it looks like it can be built as an ELSA. They don't have to certify it (that doesn't really make that much difference to a homebuilder), but is the battery used to power the ignition system? Is it used for starting? Both of those instances have completely different requirements. I've been using lithium batteries for years in tools, but they have their own special chargers, and, on the ones I've used on my power tools, they cannot be allowed to run all the way down. They are also very heat sensitive, especially for charging. Where I live, daytime temperatures are often over 110F in the summer. I'm all for innovation and experimenting, but before I'd put a Lithium battery of any kind for my primary battery in an airplane, I'd sure want to know what the limitations are. It cost Boeing multiple millions of dollars because all those questions weren't thoroughly addressed on the Dreamliner. I urge you to read Bob's article. To add to the above: Bob discusses the various factors which have to be considered when using a lithium battery. Among them are the special ways in which the batteries need to be charged. There are many examples of Lithium batteries exotherming to the point that they catch fire when they are being charged. My lithium batteries need to be recharged in a cool place because they have a temperature monitor. Just yesterday, a girl had her phone recharging under her pillow, (phones don't have temperature monitors) and it caught fire when the battery exothermed. All of my lithium batteries for my tools have temperature monitors that don't allow them to be charged over a certain temperature. I have sometimes resorted to putting them into a freezer for a short time so they would be cool enough to charge. Bob Nuckolls article goes much further into the whys and hows of lithium battery usage in airplanes. Everyone is free to do what they wish, but I urge everyone who's thinking of using lithium batteries for their airplane to read the article. On Mon, Jul 28, 2014 at 2:11 PM, Dan Branstrom via KRnet < krnet at list.krnet.org> wrote: >> A while back, one of the posters here was interested in using a much >> lighter Lithium battery for their plane. >> >> Bob Nuckolls, who is an expert on electrical systems in airplanes, has an >> article on Lithium iron-phosphate batteries in the latest Kitplanes, >> entitled "Battery facts and fables: lithium lead-acid equivalency. It >> starts on page 63 of the September 2014 issue. >> >> At this point, he doesn't endorse Lithium batteries, mostly because of the >> lack of information that manufacturers have provided to him. He also delves >> into the special issues that a person using a lithium battery might >> encounter with their use. Those don't seem to be addressed by >> manufacturers. He is promising follow up articles. >> >> I found it interesting reading. >> >> Dan Branstrom >> >> ___ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >> please see other KRnet info at http://www.krnet.org/info.html >> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change >> options >> > > -- > > Subject: Digest Footer > > ___ > See KRnet list details at http://www.krnet.org/instructions.html > KRnet mailing list > KRnet at list.krnet.org > http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org > > > -- > > End of KRnet Digest, Vol 2, Issue 194 > * -- Please do not forward this email without deleting the email address of the sender. Please do not forward any emails without using the Bcc option (Blind carbon copy). If you just use the forwarding option, internet spammers and crooks can ?catch? all the email addresses and send your friends and family messages that appear to be from you.
KR> Lithium Ion Batteries.
A while back, one of the posters here was interested in using a much lighter Lithium battery for their plane. Bob Nuckolls, who is an expert on electrical systems in airplanes, has an article on Lithium iron-phosphate batteries in the latest Kitplanes, entitled "Battery facts and fables: lithium lead-acid equivalency. It starts on page 63 of the September 2014 issue. At this point, he doesn't endorse Lithium batteries, mostly because of the lack of information that manufacturers have provided to him. He also delves into the special issues that a person using a lithium battery might encounter with their use. Those don't seem to be addressed by manufacturers. He is promising follow up articles. I found it interesting reading. Dan Branstrom
KR> Apex Electronics Was: Gathering arrival
Paul Visk via KRnet wrote: >> I found the place. It's called Apex Electronic. There in Sun Valley Ca. >> Here?s there website. http://www.apexelectronic.com/ >> >> Paul Visk >> Belleville Il >> 618 406 4705 Apex Electronics is a rabbit warren of parts and wiring. There are aisles of, to put it mildly, stuff, stacked to the ceiling. Most of it is not for airplanes, so you'll have to hunt for it. They do have some A/N screws and nuts in odd sizes. For instance there was a box of thousands of A/N stainless 4-40 machine screws, about an inch long. There was a box of toggle switches, DPDT on-on for, if I can remember correctly, $12.00 Wire is sold by the pound. You'll have to go through the spools and find what you want. They have all sorts of colored insulation on them. The wiring you want is insulated with Tefzel. They have shrink tubing, sold by the foot, of diameters up to 4". It's a couple of miles south from Whitman airport. I had to go to the San Fernando Valley with someone, so while they were at an event, I stopped by there. Parking is easiest on San Fernando Road. My advice is to go there with a shopping list. Get what you need, then wander around. They have some odd stuff that is interesting. I ended up buying an extra remote for my satellite box. There were a bunch of them, most of them messed up. I got it for something like $3.00 It works perfectly. You'll find oscilloscopes, and all sorts of electronic test equipment, outmoded but usable. Enjoy. Dan Branstrom
KR> anybody_tried_this_for_high_altitude_flying?_Look_at_this_on_eBay
Think about this: to concentrate the oxygen in the surrounding atmosphere, it takes energy. Lots of it, and that is even on the ground, where there is much more oxygen available. If you're going to put an oxygen concentrator in an airplane, you'd better have one large alternator or several very large batteries, even when the plane is flying at low altitude. Since the number of oxygen molecules are far fewer at the altitudes where you require oxygen, the concentrator has to work that much harder. If the power goes out, you're out of luck, aren't you? To be safe, you'll need to descend immediately. Out West, that may not be a good alternative. Considering cost, weight, complexity, the amount of horsepower needed to generate the electricity, I wouldn't even consider it. There Ain't No Such Thing As A Free Lunch. TANSTAAFL - courtesy Robert A Heinlein. Even if the generator is free, the cost of your time will be substantial. Do you want to spend your time experimenting (along with an oxymeter to make sure you're getting what you need), or flying? The OXYFLY unit that is designed for high altitudes takes 15 amps at 28 volts. That's 420 watts. Probably, that's overkill, and you might be able to adapt a smaller, ground-based one, but even if you find one that's suitable that takes half the power for just you, that's still 210 watts (15 amps at 14 volts) draw on your system. Dan Branstrom
KR> Free, cheap flight planning software.
The latest Flying magazine has a spread on different Android flight planning programs. I know that isn't what you wanted, but I thought I'd mention it. Dan Branstrom.
KR> 0=200 rpm limit
I've got some experience with the GO-300 on a Cessna 175, as well as having had discussions with people familiar with 175s as owners. The consensus is that the problem is not with that engine, but with operating technique. If the GO-300 is operated at the rpms of an ungeared engine, such as 2700 rpm, it tends to overheat, thus needing cylinder replacement. Operated at >2900 rpm, the engine is quite comfortable, and overheating does not occur, and it is, IMO, reliable. Pilots who are used to ungeared engines cringe at those figures, because that is far above familiar redlines, so they try to operate it at ungeared engine speeds, such well below 2700 rpm. That's a costly mistake, and it gave the 175 what I consider an undeservedly poor reputation. That has made the 175 cheaper than they deserve to be. Operated correctly, the consensus is that the engine usually makes TBO. Of course, there are a lot of other factors that influence reaching TBO, but low rpm operation definitely reduces it on that engine. BTW, because it was swinging an 84" prop that was possible because the gearbox was atop the engine and gave greater ground clearance, it sure helped performance on the Cessna 175. It matched the performance of a 175 that had been converted to a Lycoming 0-360 with, as I remember it, a constant speed prop. Having a 6 instead of a 4 also meant smoother operation. A bigger prop doesn't necessarily mean more efficient operation, nor does a constant speed prop, because there are a lot of variables (added weight is one of them). The 175 had the prop sized and geared right for the engine and airframe by Cessna engineers. On 5/7/2013 9:00 AM, krnet-request at list.krnet.org wrote: > Something to remember is that Continental also made a GO-300 that uses the > same rods and bearings, and a slightly different piston. Same compression, > not really any beefier, but turns 3100 or 3200 RPMs. They are also a 1200 > hour TBO, just for comparisons sake, and often times don't make that.
KR> brake cylinder manufacturer?
Oscar is right. Be careful about what you put in your brake systems. Locally, we're lucky to have a local supplier of hydraulic fittings who is also a pilot. He is very careful about what he sells, and is very knowledgeable. His O rings meet aviation specs for brakes. Many pilots go to him and buy O rings, and there's never been a problem. The price is 1/4 or less than ACS, and it's quicker. On 2/24/2013 11:30 AM, Oscar Zuniga wrote: > By the way, Mark, by using the wrong parts on the brakes on my Piet, I found > that some O-ring materials aren't happy with brake fluid.
