How much speed do you pick up by removing the strobe on top of the vertical stabilizer and I wonder how much speed you would pick up by removing the ADF long wire that goes up to the top of the tail?? This is on a 1974 Super Viking. I never see the published speeds out of this plane. I need to check the tach and see if rpm is right. at 2500 rpm and 24 inches at 7500 ft on a standard day I should be getting around 160 kts and I never see over 147. Hope some of you Viking drivers will respond. Thanks
another question on strobes
- Thread starter N14909
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shipchief
New member
Our 1966 260 has a long wire ant. on the top, and a fairly large teardrop ant. on the bottom. the ADF is an old Narco, and will be removed fairly soon. This analog tuned ADF actually recieves audio, and we can listen to AM radio on it rather well, but it will not "DF".
Right now we are waiting on the engine overhaul, so the flight testing for drag reduction is probably months away, but we will do it.
Additional drag is provided by 2 ea com antenae on the fuselage top, large old style strobe 'jars' top and bottom of the fuselage right behind the back com ant., a cat's whisker nav ant on the vertical stab, a short transponder whip on the belly, a full size marker beacon "sled" ant on the belly and a nice low drag DME ant on the belly.
This A/C has wing root fairings and a 3 blade prop, but no main gear doors. We have a hand held GPS to get reliable speed data, and I think I have access to a photo tach so we can get good RPM data too. We will probably use the stock continental fuel flow/pressure gauge and manifold pressure gauge for a start.
My EAA chapter (326, Puyallup WA) has scales so we can do weight & ballance for 'real life' numbers too. I think all these Viking type planes are on the heavy side. N8533R empty is 2000 lbs. Full avionics W/ auto pilot adds the weight, especially the older 'vintage' gear. I hpe to be able to weight it several times as the ship is lightened.
Right now we are waiting on the engine overhaul, so the flight testing for drag reduction is probably months away, but we will do it.
Additional drag is provided by 2 ea com antenae on the fuselage top, large old style strobe 'jars' top and bottom of the fuselage right behind the back com ant., a cat's whisker nav ant on the vertical stab, a short transponder whip on the belly, a full size marker beacon "sled" ant on the belly and a nice low drag DME ant on the belly.
This A/C has wing root fairings and a 3 blade prop, but no main gear doors. We have a hand held GPS to get reliable speed data, and I think I have access to a photo tach so we can get good RPM data too. We will probably use the stock continental fuel flow/pressure gauge and manifold pressure gauge for a start.
My EAA chapter (326, Puyallup WA) has scales so we can do weight & ballance for 'real life' numbers too. I think all these Viking type planes are on the heavy side. N8533R empty is 2000 lbs. Full avionics W/ auto pilot adds the weight, especially the older 'vintage' gear. I hpe to be able to weight it several times as the ship is lightened.
shipchief
New member
N14909;
I'm wondering if your Viking is slow for an other reason. Your speed lack sounds about right if one cylinder of your engine is not providing full power, for example, if you have a not uncommon worn cam lobe, the valve might open enough to give a good idle, and a good compression check @ annual inspection, but not give good power. Your length of take off roll would also seem long, and the rate of climb also low. This would be the case if the engine is low on power for any reason.
If you have high drag, it's probably something like maybe your main landing gear doors are being pulled open a little at higher cruise speeds. That would account for a short take off roll and normal climb rates at 110 MPH.
All the other VIKINGS in your production year have the same tail strobe, yet they make speed, so I wouldn't look there. I looked up a pic of your plane (looks nice too) and it looks like you have a small strobe jar on the tip of the vertical stab. By law, that is satisfactory, and no wing tip or belly strobe is required.
An other source of trouble is the door. Does yours fit tightly and when closed does it present a nice smooth surface for the air flow over the fuselage?
Does your plane fly crooked through the air, one wing high or the skid ball off to one side? maybe it's out of trim.
I once considered a Cruisemaster, that had little trim tabs added by the owner to straighten it out in flight. I did not buy that one, but the guy who bought it (an A&P with IA) adjusted the wing incidence and was able to remove all those little tabs.
And last, do you run your plane at a high enough power setting to go 160 Kts? I'm always cheap, so I don't like to run over 22 Squared. :wink:
I'm wondering if your Viking is slow for an other reason. Your speed lack sounds about right if one cylinder of your engine is not providing full power, for example, if you have a not uncommon worn cam lobe, the valve might open enough to give a good idle, and a good compression check @ annual inspection, but not give good power. Your length of take off roll would also seem long, and the rate of climb also low. This would be the case if the engine is low on power for any reason.
If you have high drag, it's probably something like maybe your main landing gear doors are being pulled open a little at higher cruise speeds. That would account for a short take off roll and normal climb rates at 110 MPH.
All the other VIKINGS in your production year have the same tail strobe, yet they make speed, so I wouldn't look there. I looked up a pic of your plane (looks nice too) and it looks like you have a small strobe jar on the tip of the vertical stab. By law, that is satisfactory, and no wing tip or belly strobe is required.
An other source of trouble is the door. Does yours fit tightly and when closed does it present a nice smooth surface for the air flow over the fuselage?
Does your plane fly crooked through the air, one wing high or the skid ball off to one side? maybe it's out of trim.
I once considered a Cruisemaster, that had little trim tabs added by the owner to straighten it out in flight. I did not buy that one, but the guy who bought it (an A&P with IA) adjusted the wing incidence and was able to remove all those little tabs.
And last, do you run your plane at a high enough power setting to go 160 Kts? I'm always cheap, so I don't like to run over 22 Squared. :wink: