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Airflow Systems: Difference between revisions
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==== | ===== Engine modifications ===== | ||
* send the stock flywheel in for adding the serpentine grooves. Consider sending it away for anodizing afterwards. | |||
* install 4 Lycoming P/N 38-14 studs in engine block below governor | |||
* mount B&C LX60 60A alternator using bracket FK5402-4 on right side of engine (compressor goes on left side) | |||
* use Sky-Tec 149NL starter | |||
* route governor over the top of the engine using Vans bracket VA-153-PC | |||
===== Governor ===== | ===== Governor ===== | ||
* The governor control cable needs to be routed across the top of the engine. The manual states "Reroute the prop governor control cable over the top of the engine utilizing the Van’s Aircraft bracket, part no. VA-153-PA or VA-183-PC (depending on your need). Note in the photos that the bracket may require modification to clear the pushrod tube." Neither of those parts are in the Vans store. The part is now called VA-153-PC.<br>[[File:Screen Shot 2022-07-13 at 9.34.47 AM.png|312px]] | * The governor control cable needs to be routed across the top of the engine. The manual states "Reroute the prop governor control cable over the top of the engine utilizing the Van’s Aircraft bracket, part no. VA-153-PA or VA-183-PC (depending on your need). Note in the photos that the bracket may require modification to clear the pushrod tube." Neither of those parts are in the Vans store. The part is now called VA-153-PC.<br>[[File:Screen Shot 2022-07-13 at 9.34.47 AM.png|312px]] | ||
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*You need a nutsert tool to place the nuts into the bottom skin, e.g. [https://www.amazon.com/dp/B09LV22WL7 this tool (similar to a manual pop rivet puller)] or [https://www.pegasusautoracing.com/productdetails.asp?RecID=9698 this tool (twist type)] with this adapter [https://www.aircraftspruce.com/catalog/pnpages/04-01427.php 8-32].<br>If you have a hydraulic knockout punch tool [https://www.amazon.com/gp/product/B07RT8RKQL e.g. this one from Amazon], you can make an adapter for pulling rivnuts by taking a 2 inch piece of a 3/4 steel rod, cutting a 3/4-16 male thread onto one end and an 8-32 female thread onto the other. Use several strong fender washers and two small washers to support the nutsert towards the punch tool or make a washer from 0.3 inch steel. Use a stainless steel 8-32 set screw as bolt. It takes some 6 full pump strokes to set the supplied nuts. Additional rivet nuts can be ordered from [https://www.aircraftspruce.com/catalog/pnpages/NAS1329A08K75-25.php Aircraft Spruce].<br>[[File:2022-09-04 16-18-41.jpg|500x500px]]<br>[[File:2022-09-04 16-16-03.jpg|400x400px]]<br>[[File:2022-09-04 18-07-51.jpg|400x400px]]<br>[[File:2022-09-04 18-09-23.jpg|400x400px]] | *You need a nutsert tool to place the nuts into the bottom skin, e.g. [https://www.amazon.com/dp/B09LV22WL7 this tool (similar to a manual pop rivet puller)] or [https://www.pegasusautoracing.com/productdetails.asp?RecID=9698 this tool (twist type)] with this adapter [https://www.aircraftspruce.com/catalog/pnpages/04-01427.php 8-32].<br>If you have a hydraulic knockout punch tool [https://www.amazon.com/gp/product/B07RT8RKQL e.g. this one from Amazon], you can make an adapter for pulling rivnuts by taking a 2 inch piece of a 3/4 steel rod, cutting a 3/4-16 male thread onto one end and an 8-32 female thread onto the other. Use several strong fender washers and two small washers to support the nutsert towards the punch tool or make a washer from 0.3 inch steel. Use a stainless steel 8-32 set screw as bolt. It takes some 6 full pump strokes to set the supplied nuts. Additional rivet nuts can be ordered from [https://www.aircraftspruce.com/catalog/pnpages/NAS1329A08K75-25.php Aircraft Spruce].<br>[[File:2022-09-04 16-18-41.jpg|500x500px]]<br>[[File:2022-09-04 16-16-03.jpg|400x400px]]<br>[[File:2022-09-04 18-07-51.jpg|400x400px]]<br>[[File:2022-09-04 18-09-23.jpg|400x400px]] | ||
* The holes in the scoop need to be countersunk for Tinnerman washers. A great tool is [https://www.permagrit.com/large-countersink-100-degree-no-nipple/ Countersink 100º, No Nipple, 11.5mm dia., LC5 from Permagrit] (they ship directly from England). | * The holes in the scoop need to be countersunk for Tinnerman washers. A great tool is [https://www.permagrit.com/large-countersink-100-degree-no-nipple/ Countersink 100º, No Nipple, 11.5mm dia., LC5 from Permagrit] (they ship directly from England). | ||
*The manual | *The manual has one drawing which shows the doublers are to be used for the condenser holes. The kit includes one set of doublers. Consider cloning the doublers and using them on the firewall and the condenser holes. The holes in the doublers are a bit too small for the 90 degree fittings when used for the condenser, so widen them accordingly. The doublers can be riveted to the inside of the bottom skin using 4 AN470 4-4 rivets:<br>[[File:2022-10-29 18-38-22.jpg|400x400px]] | ||
* In order to mark the two holes for the condenser fittings one needs to make a template. A good way is to first make very large holes roughly where they need to be, then pass the fittings through those holes (make sure they are perpendicular to the condenser), then take additional snippets that have half-hole cutouts at their edges and tape them to the template so the half-holes touch the fitting. | * In order to mark the two holes for the condenser fittings one needs to make a template. A good way is to first make very large holes roughly where they need to be, then pass the fittings through those holes (make sure they are perpendicular to the condenser), then take additional snippets that have half-hole cutouts at their edges and tape them to the template so the half-holes touch the fitting. | ||
*The manual doesn't state where left and right is on the master hose plan. | *The manual doesn't state where left and right is on the master hose plan. Make your own drawing based on where you route the hoses. Keep in mind that the smaller port of the condenser is the output back to the dryer. The larger one is the input from the compressor. | ||
* Check the 90-degree fittings before attaching to the condenser as there might be white powder / residue inside from the soldering process. Can be removed with a round brush and blown out with clean compressed air. | * Check the 90-degree fittings before attaching to the condenser as there might be white powder / residue inside from the soldering process. Can be removed with a round brush and blown out with clean compressed air. | ||
===== Painting ===== | |||
* Consider priming and top-coating the fuselage bottom skin that is underneath the scoop (primer alone is porous and not suited for wet areas). | |||
* The scoop needs to be painted before mounting it finally. | |||
** Rough up the gelcoat and fiberglass with sandpaper (150-400 grit). | |||
** Smoothen the seams between the different parts of the scoop. | |||
** Fill pin holes and rough areas with epoxy filler. Suitable filler is [https://www.totalboat.com/product/totalfair/ TotalFair]. You can smoothen the surface and transition edges with a wrinkle-free glove finger wetted with 70% isopropyl alcohol. After curing, the filler can be trimmed using a flex shaft with a conical grinder, e.g. [https://www.harborfreight.com/bench-grinder-with-flex-shaft-43533.html this grinder]. | |||
** Consider creating a smooth transition between the entry opening and the inside walls using the filler. | |||
** Spray paint the scoop first with a filler primer. Fill pin holes and sand between coats. Suitable is [https://www.aircraftspruce.com/catalog/cspages/smoothprime.php?clickkey=50760 Smooth Prime]. Then put a top coat on that matches your later bottom skin. | |||
===== Evaporator Shelf Mounting ===== | ===== Evaporator Shelf Mounting ===== | ||
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* The rivets supplied for mounting the evaporator shelf are usable but weaker than necessary. They have a marking of "OIDC" instead of a small center dimple. They are made of a soft alloy. Use proper aircraft AD rivets instead. The rivets are not used in a shear fashion, rather the shelf hangs off the rivets underneath the longeron. They need to be strong. | * The rivets supplied for mounting the evaporator shelf are usable but weaker than necessary. They have a marking of "OIDC" instead of a small center dimple. They are made of a soft alloy. Use proper aircraft AD rivets instead. The rivets are not used in a shear fashion, rather the shelf hangs off the rivets underneath the longeron. They need to be strong. | ||
* The kit has only one washer per bolt to attach the evaporator shelf to the side braces. Better to use a washer on the top and bottom to distribute forces across the soft fiberglass | * The kit has only one washer per bolt to attach the evaporator shelf to the side braces. Better to use a washer on the top and bottom to distribute forces across the soft fiberglass | ||
===== Evaporator Mounting ===== | ===== Evaporator Mounting ===== | ||
*There are a lot of loose ends when mounting the evaporator. The issue is that at the point where you would install the AC (before closing out the floor panels), the tailcone bulkhead does not have predrilled holes yet for the closeout panel as it comes from Vans. So the holes in the upper closeout that Airflow sends don't match up with any existing holes.<br>[[File:2022-09-17 19-11-03.jpg|400x400px]] | *There are a lot of loose ends when mounting the evaporator. The issue is that at the point where you would install the AC (before closing out the floor panels), the tailcone bulkhead does not have predrilled holes yet for the closeout panel as it comes from Vans. So the holes in the upper closeout that Airflow sends don't match up with any existing holes.<br>[[File:2022-09-17 19-11-03.jpg|400x400px]] | ||
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*The manual doesn't recommend what to use for sealing against air leaks. PERMATEX # 2 SEALANT seems to do a great job. | *The manual doesn't recommend what to use for sealing against air leaks. PERMATEX # 2 SEALANT seems to do a great job. | ||
===== Hose Routing ===== | ===== Hose Routing ===== | ||
* There are two options for routing the hoses: through the tunnel or within the side walls. The kit contains only the fittings for the tunnel option (which needs "Z" adapters for the condenser; for routing in the side walls, you need plain 90 degree adapters on the condenser). Specify which routing you want when ordering. Airflow will exchange the Z fittings for 90 degree ones on request however they are made to order and it takes several weeks. | *Three hose diameters are in play which reflect the state of the coolant: | ||
** #10, the thickest, for when the coolant is all gas at low pressure as it comes cold out of the evaporator back to the compressor up front | |||
** #8, mid sized, for when the coolant is compressed, hot gas out of the compressor to the condenser/scoop | |||
** #6, the smallest, for when the coolant is mostly liquid out of the condenser/scoop to the evaporator via the dryer | |||
*If you want to route the hoses along the right side of the fuse, the thicker fitting needs to be on the copilot side (the Layout diagram shows it the opposite way). | |||
* If you need longer hoses, for example for routing the hoses in the engine compartment, www.acparts.com (Aero Climate Control Inc, 2012 Industrial Bld, Rockwall, TX 75087) sells them by the foot. The #10 hose has part no 3501028 ($4.60/ft as of 11/2024) and the #8 hose has part no 3501010 ($4.17/ft as of 11/2024). The hoses that come with the AC and the one acparts.com sell are the same, Goodyear Galaxy Reduced Barrier. | |||
* There are two options for routing the hoses: through the tunnel or within the side walls. The kit contains only the fittings for the tunnel option (which needs "Z" adapters for the condenser; for routing in the side walls, you need plain 90 degree adapters on the condenser). Specify which routing you want when ordering. Airflow will exchange the Z fittings for 90 degree ones on request however they are made to order and it takes several weeks.<br>This builder log from Allen documents using the tunnel: [https://airplane.allanglen.com/2022/04/16/a-c-line-routing/ AC-line tunnel routing] | |||
*When running the hoses outside the tunnel, they recommend running them to the right side of the firewall as the left side is busy with the oil cooler. | *When running the hoses outside the tunnel, they recommend running them to the right side of the firewall as the left side is busy with the oil cooler. | ||
*Note: If you use the [https://www.aerosportproducts.com/product/rv-10-interior-panels-2/ Aerosport interior panels], keep in mind that the recessed area for maps / the cup holder occupies the space between the panel and the outer skin which is separated by U-profiles all around, where you would probably want to route the hoses through. There is room for one hose all the way on the top but a modification to the right side panel is need if you run the second hose underneath it. | |||
*No snap bushings come with the kit. You need to keep the holes as small as possible, however the hoses will probably swell a bit under pressure. A compromise is to use larger ones in non critical ribs and webs and smaller ones, or no bushing in the critical u-profiles above the main spar. Consider ordering | |||
** [https://www.mcmaster.com/catalog/5269T19 McMaster Part No 5269T19, Snap Bushings for 3/4 inch hose] or<br>[https://www.mcmaster.com/catalog/5269T107 McMaster Part No 5269T107, Snap Bushing for 3/4 inch hose, one size up and split] | |||
** [https://www.amazon.com/gp/product/B01LP4F0EU Snap Bushings for 11/16 inch hose at Amazon] or<br>[https://www.mcmaster.com/catalog/5269T106 McMaster Part No 5269T106, Snap Bushing for 11/16 hose, one size up and split] | |||
* When picking a spot on the firewall for mounting the fittings, be sure that the engine mount doesn't interfere with the fitting / hose. The bulkhead fitting plus the hose fitting add to quite some length before making a turn. If you need less space, consider using a 90 degree hose fitting with integrated bulkhead mount, e.g. for the #10 hose, part SR1723 from [https://www.acparts.com/product/90-degree-male-insert-o-ring-mio-bulkhead-10-1341047/ AC Parts]. If you buy fittings, they must be "reduced barrier" (thinner walls / smaller OD) and the o-ring type. For inside the fuselage, they should be aluminum with steel sleeves to be light but bulkhead through-wall fittings and fittings within the engine compartment are made entirely out of steel. Check with a magnet to keep them apart.<br>[[File:2023-02-26 16-59-15.jpg|300x300px]] | |||
===== Crimping Fittings to the Hoses ===== | |||
* A suitable crimper for the hoses is e.g. $224 at eBay: [https://www.ebay.com/itm/232525885895 Standard and Reduced Barrier A/C Hose Hydraulic Crimper Kit with 7pc Die Set] | |||
* Reduced barrier hoses, which are used for ACs, have a second liner on the inside of the hose to keep the gas from leaking. To protect the inner liner, the hose will go onto the fitting very easily, even with a bit of slack, this is normal. The hose sits tight on the center barb after the crimp. | |||
===== Dryer Mounting ===== | ===== Dryer Mounting ===== | ||
*Mount the dryer as shown on the drawings of the manual (half way between evaporator and side skin). Make sure it stays clear of the seatbelt shoulder harness that passes through this area. [[File:2022-10-08 18-28-13.jpg|400x400px]] | *Mount the dryer as shown on the drawings of the manual (half way between evaporator and side skin). Make sure it stays clear of the seatbelt shoulder harness that passes through this area. [[File:2022-10-08 18-28-13.jpg|400x400px]] | ||
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=====Torques===== | =====Torques===== | ||
The manual doesn't mention any torques for the fittings. The internet provides vastly different values, potentially because there are aluminum fittings and steel ones (firewall and forward, use steel fittings): | |||
* Consider using [http://rotorcraftservices.com/dev/wp-content/uploads/2014/09/IM-350-00-011-LAW.pdf this certified helicopter AC manual] which has these values on page 27: | |||
** #6 30-35 in/lb | |||
** #8 40-45 in/lb | |||
** #10 50-55 in/lb | |||
* Consider using [https://documents.holley.com/cap-365m-289_instructions.pdf this car AC manual] which has these values: | |||
** #6 11-13 ft/lb | |||
** #8 11-20 ft/lb | |||
** #10 21-27 ft/lb | |||
===== Charging the System ===== | |||
* See this [https://vansairforce.net/threads/charging-airflow-systems-ac-system.236187/ VAF thread] | |||
[[Category:Optional]] | |||