Hi Bill. I've been having a blast taking off from the carrier, but I have a question about the briefing notes for that flight. The notes say that after reaching 6000 feet you should "dump everything but 5033128n the mains; all other tanks dry." This is a very cryptic typo. What is it really supposed to say?Also some questions about carburetor heat- The Engine Warm-up checklist you supplied says to turn on the heat if below 12 degrees C, whereas the Approach checklist says to turn the heat on if the temp. is below minus 12C. Are these two numbers supposed to be the same? If so, which one is correct? (I tried both the simulator help and the Pilots Training Manual, but could not find the answer.)Finally, a general question on carburetor heat. The manual only talks about it in conjunction with either takeoff or landing. Is it also used during cruise? If you don't need it at takeoff do you still turn this heat on if the outside temperature drops to a particular range?Thanks.

Hi Bill,Oops! No one spotted that one before, including me. :-( If you pull out the printable, doc version of the Doolittle Raid Reenactment briefing from the FS2002aircraftB-25J Briefing TimeDocumentsdoolittle folder, you'll find it reads 50%. Apparently FS kneeboards don't like the percent symbol.I am going to refer your questions on the carb heat to the gentleman who organized and tested the checklists for us. Howard Sodja, one of our BT Beta Team, is a pilot of forty year's experience and a professional writer. Besides the checklist and reference pages, which he extracted from various B-25 manuals and adapted to FS and our model, he wrote the original article, "A Brief History Of The B-25 'Mitchell' Medium Bomber", featured in the supplementary B-25J Mitchell 'Briefing Time' Multi-Media CD. That CD also contains four other historic, vintage manuals, 500 digital photos, and 48 minutes of video.I'll give Howard a shout and ask him to educate us.Bill Rambow MAAM-SIM - Rambow, Visser, Banting, and Younghttp://www.fssupport.com/maam_sim/maamsim_logo.gif

On carb heat, I used to check it during cruise (on my home built Corben Baby Ace, C85 equiped) if conditions were right for ice. Apply the heat and if the RPM INCREASES, look out, you were gathering ice. If it drops all is fine as it should be...Carb ice likes to start with changes in throttle settings, all at the worst possible times....lol Interestingly enough, carb ice was a bigger problem in summer with high humidity than in the winter.. Mike B.

Howard Sodja had trouble posting here and asked me to put it up for him:Hello.I composed the BT checklist by combining one B-25C-D and four B-25J flight handbooks and manuals. MAAM had no "real-life" military-issue checklist for the B-25J, but I had one for the B-25C-D, which I modified to conform with the four B-25J manuals and handbooks. Each book had some variations on sequences and procedures, so, when in doubt, I used the procedure now being used by the MAAM crew in their "real life" BT.The lack of carb heat info resulted from my earlier indecision on whether to list carb heat in the "Climb," "Cruise," and "Descent" sections, or just state once how to use it in all en route phases of flight, except as noted. Obviously, this conflict was resolved by my forgetting to add it at all! The B-25C-D checklist simply says "Carb Heat- As needed."I suggest that you add "Carb Heat

Well, I'm sold. Guess I'll order the other CD. Thanks for the information.

Hello again,I wrote my reply on carburetor heat as soon as I read Bill's question. Afterwards, I began to wonder why I had so much indecision when I first wrote the checklist, as what I wrote seemed easy enough. Then it struck me: during a climb the MP steadily decreases, and during a decent, it increases. My "operating note" only applies during level cruise. My memory seems to have a slight time lag.As a single-engine VFR private pilot, I can easily tell when my bird is not climbing as fast as normal, and the engine is slightly rough. Whenever I have experienced these condition while climbing, carb hear would always smooth out the engine and restore my climb rate (sometimes after a brief heart-stopping cough or sputter as the ice breaks off and is ingested ;-) However, I do not know if this method of detecting Carb ice is practical with two loud radials.Another issue is that, as a VFR pilot, I never have flown into known airframe icing conditions, nor have I flown through clouds, which will create carb ice when the OAT is above freezing. The higher the humidity, the higher the temperature can be for carb ice. The B-25 manuals and handbooks say to use carb heat in "known icing conditions," so I assume B-25 pilots would apply heat under the above two conditions.Every engine has its own carb icing characteristics. In my experience, Continental engines with carburetors are much more susceptible to carb icing, even in the summer, if the humidity is high. In contrast, I have rarely had carb ice in a Lycoming with carburetors. During the evolution of the B-25, a change was made to Holley carburetors because they were less prone to induction icing.I will check with MAAM BT flight crew to find out how they use carb heat during climbs and descents to clarify these fine points. I do not want to post my assumptions as answers. Stay tuned for how Russ handles carb ice on climbs and descents.Howard

As part of my IMC training and when flying with IR instructors, I have spent a fair amount of time around cloud over the last year or so. With an OAT of around 9-10 degrees C and full power applied, I have sometimes found that the C152 needs to be flown with a certain amount of carb heat permanently applied to keep the engine running with even enough power to climb at times.Unfortunately, MS really doesn't seem to handle carb heat correctly, as you don't experience a visible drop in power when applying it. It does seem to clear ice well enough though and I can tell you one specific place where carb heat should always be applied... Downwind checks:Brakes OffUndercarriage DownPitch CoarseMixture RichFuel On and SufficientInstruments Set and CheckedCarb Heat Hot (wait a few seconds...)Carb Heat ColdHatches and Harnesses Secure.I have found carb icing on cold days even when clear of cloud, at low power levels, so that check really is important in case you have to go around.With respect to climbing and descending, you use it in the climb when losing power and only sparingly then, in the descent whenever the tach or MP gauge is below the green arc. That's the way I was taught, but it doesn't seem to be common across all courses and even instructors at a single school!Ian P.:-halo

Hi Gents,Lively discussion here. :-)I just returned from Reading and am happy to tell you that Russ Strine - in case you have been living under a rock, BT-wise, he's the MAAM President and Chief Pilot - has agreed to post answers on this forum.He's a busy man, as you might imagine, so don't look for him to be constantly lurking here to jump on your questions, but I will try to alert him when something needs his expertise. This being a case in point, he can tell you exactly how carb heat is handled in the B-25J, if you will stand by. Bill Rambow MAAM-SIM - Rambow, Visser, Banting, and Younghttp://www.fssupport.com/maam_sim/maamsim_logo.gif

Hi Bill!That's good news! A new icon to add to my little gallery of BT-heroes: Bill, Jan, Fred, Rob and now Russ (wide and wicked grin)!Seriously: since I received Briefing Time, I have not flown anything else! And what's more (this is especially to Jan): I exclusively use Charley (the VC)! I'm as pleased as a bugger in rugby! If BT is the shape of things to come, then I will spend my time increasingly in the virtual word of FS, instead of in the real world of mortgages, work, nagging wife, bills, and the necessity to provide food.Be well!Jaap Verduijn.

Hello Ian,Thanks for your input. I held off on my reply to see if anyone else had any more comments on this topic.I soloed in a J-3 Cub, earned my private pilots license in a Cessna 140, and have logged most of my time in the Cessna 150. In all of these aircraft, I was taught to never apply partial carb heat, but always have it either full on or off. I was warned by more than one instructor that applying partial carb heat has the potential of actually creating carb ice that will be difficult to remove later with full heat.Your remark, "I have sometimes found that the C152 needs to be flown with a certain amount of carb heat permanently applied to keep the engine running with even enough power to climb at times." Motivated me to break out my old 1961 flying bible, "The Student Pilot's Flight Manual." When discussing heavy carburetor icing conditions, this manual says: "Some pilots recommend partial heat in this condition, but the best answer is to use full heat as soon as signs of icing appear and to continue using it as long as necessary, realizing that some power is lost because of the warmer air."For those unfamiliar with the fine points of carb icing, the manual goes on to say, "Carburetor icing boils down to this: It isn't the heat, or lack of it, it's the humidity. At very low temperatures

Howard: I tend to fly C152s, simply because the C150 at the club I fly with is an Aerobat and, to say the least, has a "slightly odd" seatbelt system, which I loathe. It also doesn't like starting, so I stick to the more predictable C152-IIs.Unfortunately, neither aircraft type has a carb air gauge, so you are kind of limited to "digital" use of the carb heat on these - it's either fully on or fully off. The new 172SP is the only one I would even think about using partial heat on now and I don't fly that, because my currency has lapsed (the club has quite tight rules, because of the number of bent aircraft they have had...) In the "a certain amount" comment, I wasn't intending to imply partial carb heat, but instead that full carb heat was applied for certain amounts of time... reading it again, I should have phrased it totally differently. My bad. Sorry! :-(To be honest, I've never had a problem with carb icing, following the "use it outside the green power arc and when you get power loss" rules. I also await Russ's input with great interest! :-)Ian P.:-halo

Hello Ian and Mike,I had forgotten to comment on remarks you both have made.Mike, your C85 is the same engine the Cessna 140 has. You deal with icing as I did in the Cessna 140, and later the 150. When I lived in Miami, I, too, had found icing to be more of a problem in the humid summer, and not the colder but dryer winters. However, now that I live in the San Francisco Bay area, I can get carb ice all year around. This is because the prevailing westerly winds off the ocean keep moist marine air, which is usually not far from the dew point, over the area most of the time. Ian, thanks for the clarification on what you meant to convey. The three of us are all in agreement. I also agree with you that FS2002 and all the earlier versions do not handle carb icing and heat accurately.As for your remark, "To be honest, I've never had a problem with carb icing, following the 'use it outside the green power arc and when you get power loss' rules.", while those procedure will keep any engine from choking to death on ice, I believe that having a Lycoming in the Cessna 152 is a big help. Also, perhaps you live inland and fly in dryer air than I do.It has been my experience that in good (bad?) icing conditions, carb ice builds up faster in a small Continental than in a similar Lycoming engine. When I am alert, I never have a problem catching an ice build-up. However, if I become temporarily distracted by some pressing in-flight activity that requires my full attention for a short time, occasionally, by the time I recheck my RPM and notice a drop, ice has built up enough to cause my engine to briefly stumble as it chokes on a chunk of ice dislodged by the carb heat. After all of these years, I still get a shot of adrenaline whenever this happens. Fortunately, this does no happen often, but when it does, it definitely gets my attention :-).In contrast, a few years ago I quit my flying club and have since been flying with two friends of mine who have built Lycoming-powered aircraft, an RV-4 and RV6A. We have all noticed that we rarely have to use carb heat, compared to when we flew Cessna 150s. The question yet be answered is how does the Wright R-2600-13 Double-Cyclone handle carburetor icing?It has been nice chatting with you on this subject that is important to all pilots.Howard

Since Russ can not easily get on line, I have offered to post his answers to questions posted in the forum. He has faxed me six pages of handwritten notes and here is the first subject:********************************************************CARBURETOR ICEThe B-25 models were originally equipped with a Holley carburetor. The Holley carburetor was fairly susceptible to carburetor icing and carburetor heat was used as a routine practice, checking carburetor operation prior to take off and then using heat in flight as required, and again prior to landing to clear out any ice. Proper carburetor management in flight would be done by maintaining the carb air temp either below or above the icing range which is from 0 degrees C to plus 10 degrees C. Below these temps it is generally too cold to form ice and above, it is too warm.Very near the end of B-25 production, the Bendix pressure carburetor was utilized instead of the Holley. (Ed. note: BT has Bendix carbs) Due to design, the Bendix carburetor is not as susceptible to icing as the Holley was, and the use of carburetor heat is not necessary as a standard procedure. Therefore it is only necessary to check that the controls work during run-up procedures and that the doors inside the air-scoops are open and the controls are in the corresponding positions.Russ StrinePresidentMid Atlantic Air Museum************************************************Bill Rambow MAAM-SIM - Rambow, Visser, Banting, and Younghttp://www.fssupport.com/maam_sim/maamsim_logo.gif